|“||You know, I've... I've been here for a very long time. And I remember many things. I remember being at a shoreline, watching a little gray fish heave itself up on the beach and an older brother saying, 'Don't step on that fish, Castiel. Big plans for that fish.' I remember the tower of Babel... all 37 feet of it, which I suppose was impressive at the time. And when it fell, they howled divine wrath. But come on. Dried dung can only be stacked so high. I remember Cain and Abel... David and Goliath... Sodom and Gomorrah.||”|
— Castiel explaining his early life
in The Man Who Would Be King
Although not much is known about Castiel's early life, as an angel, he has existed for millions, if not, billions of years. He watched as the first fish emerged from the ocean. Even Metatron hinted that Castiel has "been around since scaly things crawled up out of the muck." Naomi also once said that Castiel has, as she put it, "been unstable in the past." Additionally, discussions with Uriel suggest the pair were children by Angel standards when Lucifer rebelled against Heaven and refused to bow down to humanity. While his brother was enthralled by Lucifer's power and charisma, Castiel remembered being frightened and disturbed by the rebellious Archangel.
Castiel had been stationed on Earth for at least 2,000 years while being in the garrison commanded by Anna, who became very close to him, which also contained Uriel, Balthazar, Hester, Bartholomew, Ishim, and Benjamin. Castiel was present when the world was first created, making him over several thousands years old going by the biblically time (Uriel also made reference to questioning 'How long have I served' as '6 or 7 centuries'). He also witnessed Cain killing Abel. He also watched them build the Tower of Babel, David killing Goliath, the destruction of Sodom and Gomorrah, and among other historic and Biblical events. He also knew a Prophet named Luke that authored two books in the Bible. He also witnessed the evolutionary struggle between Homo sapiens sapiens and Neanderthals and was hoping that the latter would survive because of their superior poetry (though this particular opinion and reasoning may have just been madness).
In the 1900s, Castiel was a part of Ishim's flight and used a female vessel. In 1901 this flight of angels came to Earth to kill Akobel, an angel who had supposedly fathered a Nephilim with Lily Sunder. After Akobel was captured, Castiel listed his crimes before he was killed. Castiel and the rest of Ishim's flight then waited outside for Ishim to kill the Nephilim, unaware that he was using them to get revenge on Lily whom he was obsessed with and who didn't have a Nephilim daughter. Sometime after, Castiel joined another garrison, led by Anna Milton, whom Castiel had become close with. After her fall, Castiel became the garrison leader, which consisted of Uriel, Balthazar, and other angels.
In 2008, Castiel spoke with his true vessel, Jimmy Novak, in Pontiac, Illinois. When Jimmy was watching television, Castiel's voice distorts the picture and caused him to scream in pain and his body to spasm until he finally blacked out. Later, Castiel told Jimmy to put his arm in boiling water and that he would be unharmed as a way to prove his faith. With his wife believing that he was going crazy, Jimmy asked Castiel what he wants from him and how he can help. Castiel explained that he needs to use Jimmy Novak as a vessel, to which Jimmy agreed to as long as his family is protected. After receiving consent, Castiel possessed Jimmy Novak. Before he left, Castiel was confronted by Jimmy's daughter, Claire, and told her that he is not her father.
|“||I am not here to perch on your shoulder. We had larger concerns.[...] We tried. And there are other battles, other seals. Some we'll win, some we'll lose. This one we lost. Our numbers are not unlimited. Six of my brothers died in the field this week. You think the armies of Heaven should just follow you around? There's a bigger picture here. You should show me some more respect. I dragged you out of Hell. I can throw you back in.||”|
— Castiel to Dean
in Are You There, God? It's Me, Dean Winchester
When Dean Winchester broke the first of the 66 Seals that would allow Lucifer to walk free, the angels took action. They fought their way to Hell and Castiel freed Dean from the pit. Dean awoke in a grave and made his way to the surface, not knowing how he had been resurrected; the only clue he had was his healed body and a large imprint of a hand near his shoulder. Castiel attempted to speak with Dean in his true voice on two occasions but discovered Dean wasn't one of those who could understand him.
After reuniting with Bobby Singer and Sam, Dean tried to learn what had rescued him from Hell. He also discovered that he'd been dead and buried for four months. Dean's group met with Pamela Barnes, a psychic who gave them Castiel's name and tried to get his true visage though Castiel warned her to turn back but she didn't heed it and her eyes were burned, blinding her. Castiel also killed the demons in a diner Sam and Dean visited, one demon telling Sam its the end.
Eventually, Dean took matters into his own hands and with Bobby's help, set a trap for the creature and protected himself and Bobby with multiple Devil's Traps and other anti-demon devices. Castiel arrived and the hunters shot at him as he passed through the Devil's Traps with ease. Castiel identified himself as the one who saved Dean before he was stabbed by him with Ruby's knife but it had no effect and Castiel quickly knocked out Bobby with a mere touch. Castiel explained who he was to Dean, telling him "I'm an angel of the Lord". Dean didn't believe him, thinking there was no such thing as angels and Castiel criticizes his lack of faith before he reveals his Angel's Wings to prove his claims. Though surprised, Dean then brings up what Castiel did to Pamela as Castiel brings up he did warn her since his true form was overwhelming. He then tells Dean that his true voice was the same shriek Dean heard at the gas station and motel so he took on a vessel to better communicate. Dean then asks why he was saved as Castiel notes Dean didn't he deserved to be save before he tells him God has work for him.
After people who were supposed to be dead seemed to be rising from the grave, Castiel appeared to Dean in a dream and explained to him that this was one of the 66 Seals, "The Rising of the Witnesses." Castiel told him that Lilith was attempting to break 66 of the seals which would lead to Lucifer walking free on Earth and then the Apocalypse would begin. The Angels had been fighting to stop the demons, but the odds were against them. He explained to Dean that he must help stop the breaking of the seals as well. Castiel also showed that he was not a force to be underestimated or even taken lightly as in a chilling tone, he told Dean to start showing him some respect or he'd change his mind and throw him back into Hell again.
One night when Dean was asleep, he woke up to find Castiel sitting beside him. Castiel, without speaking, tapped Dean and brought him back in time to an important few-day period in 1973. It showed Dean the connection between Azazel and Mary Winchester, and answered questions that had always been on his mind. Castiel said that the reason he had brought Dean back to that period was to make sure that he was caught up with all of the facts. After Dean indirectly set the future in motion, Castiel appeared to take him back. Castiel explained that the angels are still unaware of Azazel's endgame. Castiel also told Dean about Sam's developing abilities and that he was going too far down a dark path and that if Sam did not stop using his powers, then the angels would kill him.
|“||Your brother is heading down a dangerous road, Dean. And we don't know where it leads. So stop it ... or we will.||”|
in In The Beginning
During Metamorphosis, Castiel is mentioned to Sam by Dean as the one who told him about his usage of his powers.
Sometime later, Castiel and his partner Uriel met with the Winchesters when they were in the middle of hunting a witch. Castiel met Sam for the first time as the latter was excited to meet him. Castiel told Sam that he was happy that he stopped using his psychic powers. The angels explained that the witch was trying to summon the demon Samhain from Hell and that this was another one of the 66 Seals. The angels said that they would have to destroy the entire town and all of its residents to ensure that the seal would not be broken. The brothers argued against this and assured Castiel and Uriel that they could stop the witch from summoning Samhain. While Uriel wanted to smite the town anyway and drag Dean and Sam away, Castiel agreed with them, later discussing with Uriel his disdain for humanity and their true orders. Unfortunately, the Winchesters failed and Samhain rose, breaking another seal. After Sam exorcised Samhain with his powers and stopped him, Castiel met with Dean in a park and revealed that the angels true orders were always to follow Dean's orders, not to smite the town and that this was a test of Dean's battlefield leadership. Castiel reveals that he always hoped that Dean would chose to save the town whether or not they failed and that he secretly harbors doubts about Heaven and its plans.
|“||You misunderstand me, Dean. I'm not what you think. I was praying for you to save the town [...] These people ... they're all my Father's creations. They're works of art. [..] I'm not ... a hammer, as you say. I have questions, I have doubts. I don't know what is right or what is wrong anymore, whether you passed or failed here. But in the coming months, you will have more decisions to make. I don't envy the weight on your shoulders, Dean. I truly don't.||”|
— Castiel's hidden compassion
in It's the Great Pumpkin, Sam Winchester
When the angels learned that a woman named Anna Milton could listen in on angel's conversations they grew worried. If the demons were able to get to her before them, the demons would know everything that the angels were planning. But Castiel knew the truth: Anna had once been his angel superior Anael who disobeyed. She cut out her Grace and fell to Earth, where she was reborn as a human. Castiel and Uriel knew though that the only way to ensure the safety of their plans were to kill Anna. While Castiel was hesitant about this, Uriel enforced the idea that it was absolutely necessary.
Castiel and Uriel found Anna along with the Winchesters. The angels ordered Sam and Dean to hand over Anna, but they refused. The angels attacked them and almost retrieved Anna, but were sent away by a ritual Anna performed. They later were able to find Anna with the Winchesters again, but soon discovered that they had been led into a trap when Alastair arrived with a group of demons. The angels and demons fought over who would take Anna with Castiel fighting Alastair. Castiel proved no match for the demon, with his powers being useless, but Dean saved him despite being on opposite sides of the Anna situation. In the end, Anna retrieved her Grace and became an angel again and Alastair's body was destroyed, defeating him. Grateful for Dean saving him, Castiel held Uriel back from attacking Dean in revenge and they left to chase after Anna.
When Alastair tried to break another seal by killing two Reapers on the night of the Solstice, Castiel managed to capture him having pretended to be Bobby to send the Winchesters after the seal. The angels held Alastair captive and when seven angels had mysteriously been killed, Castiel assumed that demons were behind the attacks. At this time, Castiel is put under closer watch by the angels, who believe him to be developing human emotions. He and Uriel recruited Dean to interrogate the demon. Castiel had grew self-conscious when Dean brought up Pamela's death and him burning out her eyes. Dean later spoke with him and asked him about his taking orders from Uriel as Castiel reveals he was demoted for getting too close to Dean.
During the interrogation, Anna returned and spoke with Castiel. She told him that she knew how he was feeling and that he was beginning to develop human emotions. Castiel refused to believe this and yelled at her, causing her to leave. Shortly after, the Devil's Trap Castiel had made to hold Alastair somehow malfunctioned and Alastair nearly killed Dean. Castiel fought the demon but was almost defeated when Sam came to his rescue, using his psychic powers to kill Alastair to Castiel's shock after torturing out of him that the demons weren't responsible for the angel deaths. While visiting Dean at the hospital, Sam criticized Castiel for being so cold-hearted as to risking Dean's life. This sunk into Castiel's head and he went to Anna for help, telling her he needed to know what to do; she told him it was time for him to decide on his own for once. Castiel investigated the broken Devil's Trap further and learned that it was Uriel who was behind the malfunctioning Devil's Trap and the angel killings.
Uriel reminded Castiel of the times when Lucifer was one of the greatest angels and also spoke about how God isn't doing anything and they must follow someone who would. Castiel refused and the two angels fought. Castiel was soon overpowered by Uriel and was beaten down but was saved when Anna appeared and killed Uriel with his own Angel Blade. Castiel then went to Dean and confirmed that Dean was responsible for breaking the first seal by giving in to Alastair's torture. Dean begged Castiel to find someone else because he wasn't fit to stop the Apocalypse.
Castiel later appeared when Dean interrogated Chuck Shurley, who was writing a book series based on the Winchester brothers, explaining that Chuck was a Prophet of the Lord. When Dean prayed for guidance, Castiel appeared and Dean asked him for help in saving Sam from Lilith, Castiel was initially hesitant to help, as Dean was angry and promised not to help him in the future. Before Dean could leave, Castiel dropped him a hint by telling him that Prophets are protected by Archangels, and that if a Prophet is in the same room with a demon, then the archangel will immediately descend to smite the demon. This caused Dean to get the idea to retrieve Chuck and put him in the room with Lilith, Dean thanked Castiel who wished him luck. Dean got Chuck in the room with Lilith which caused her to retreat while saving Sam.
Castiel then came to Dean while he was dreaming and told him to meet him at a certain location, saying that he had something to tell them. But when Dean and Sam arrived, they found him unconscious in a wrecked building with dead demons. When he awoke, the brothers found that Castiel had abandoned his vessel, Jimmy Novak, who describes being possessed by Castiel like "being chained to a comet." When Dean, Sam, Jimmy and Jimmy's daughter, Claire, were being held hostage by demons, Jimmy was shot and Castiel returned to possess Claire and helped save them all. Castiel was disgusted to see Sam consuming demon blood to exorcise the demon possessing Amelia Novak.
Castiel then told Jimmy that he kept his promise to protect his family and tried to comfort a dying Jimmy by stating he will take Claire as a host, Jimmy pleaded with Castiel to leave his daughter and take him back as a host and Castiel accepted. When Dean asked Castiel what he had been trying to tell him, Castiel coldly brushes him off and says his allegiance now is only to Heaven.
|“||I learned my lesson while I was away, Dean. I serve Heaven. I don't serve man, and I certainly don't serve you.||”|
— Castiel's changed loyalties
in The Rapture
Later in When the Levee Breaks Castiel was summoned by Dean, who was screaming for three hours for help. When Castiel arrived, Dean asked him what happened in Heaven, but Castiel wouldn't say. Then Castiel recruited Dean in the service of God and his Angels. Castiel told him to wait till the Angels summons him. A few hours later he freed Sam from Bobby's panic room in which he was held captive, because of his addiction. Later Anna confronted Castiel about why he released Sam. Anna said that Sam was even worse than they had expected. Castiel told her that he has his orders to follow and said Anna shouldn't have come. The next moment two Angels stood beside her, and took her captive.
Later Zachariah brought Dean to a chamber, so he would be safe for the release of Lucifer. Zachariah told him that the final seal would be broken that night. Although he had a fight with Sam, Dean tried to contact him on his cellphone, leaving a message on his voicemail. Later, Dean wanted to talk with Sam and summoned Castiel by breaking a Stone Angel on one of the tables. Dean asked to visited Sam, but Castiel said he could go everywhere except to Sam. Dean asked what they were going to do with Sam. Castiel said that Sam is going to do it to himself, but he didn't want to say more. He said it was his destiny. Dean said that destiny was just a bunch of lies, to keep him in line. Dean tried to persuade Castiel to help him, but Castiel said that they would be all be hunted and be killed. In response, Dean said to him that this is worth dying for. But to Dean's disappointment, Castiel refused and Dean ordered him away. Castiel tried to get Dean to listen, but left when he refused.
Shortly after, Castiel confronted Dean and drew an angel banishing sigil on the wall with his own blood after putting his hand over Dean's mouth to stop him from shouting until he realized Castiel was helping him. Then Zachariah appeared and demanded to know what he was doing. Finishing the sigil, Castiel pressed his bloody hand on the sigil, banishing Zachariah. He then told Dean Zachariah would be back and said that Lilith is the final seal and that Sam is going to break it. He said he knew someone that knew where Sam was and teleported Dean with him.
Castiel teleported Dean and himself to Chuck, the prophet of the Lord. Chuck was confused and said that this is not supposed to be, for this was not in the story. Castiel said that they would make it up. When they found out that Sam was at Saint Mary's, Chuck's computer goes off and bright light fills the room. Castiel said it is the Archangel and teleported Dean to Saint Mary's, so that he could hold the Angel off. At Chuck's house, Castiel looks up at the bright light. Seeing the angel's expression, Chuck puts his hand on Cass' shoulder, but when Castiel gives him a look, he removes it.
|“||There is someone besides Michael strong enough to take on Lucifer. Strong enough to stop the Apocalypse. [...] The one who resurrected me and put you two on that airplane. The one who began everything. God. I'm gonna find God.||”|
— Castiel's mission
in Good God, Y'all
After witnessing the release of Lucifer from Hell, Dean and Sam went to Chuck's house to find Castiel. There they were told by Chuck that the Archangel smoked Castiel – literally – and they even find one of his teeth tangled in Chuck's hair. Later, when the Winchesters are trying to track down Michael's sword in their father's old storage unit, Zachariah and his angels arrived to inform Dean that he is Michael's sword—in other words, Michael's vessel. When Dean refused to give his consent for Michael to possess his body, Zachariah started inflicting various kinds of physical pain on him and Sam (breaking Sam's legs and removing his lungs, and giving Dean stage-four stomach cancer), all the while refusing to kill them. Castiel then miraculously appeared and dispatched Zachariah's men, Zachariah questioned his return. Castiel hinted at God's involvement at his return and the rescue of the Winchesters. He then forced the scared Zachariah to heal the Winchesters and leave, to which Zachariah complied. He then used his powers to carve Enochian sigils on their ribs, keeping them hidden from all demons and angels, including Lucifer and himself. Castiel confirmed his death but when Dean asks him how is he alive, Castiel disappears before giving him an answer.
After rebelling against the angels, Castiel goes on a mission to find God in hopes he will be the one to stop Lucifer. He uses Dean's amulet for this, which is said to glow hot in God's presence. It's revealed Castiel's powers are also diminished, cut off from Heaven, and he is at first mad at Sam and Dean for failing to stop Lucifer's rise when he literally "lost everything". However, despite his, he continued to be invaluable ally to the brothers saving them on numerous occasions.
|“||I killed two angels this week. My brothers. I'm hunted. I rebelled. And I did it, all if it, for you. And you failed. You and your brother destroyed the world. And I lost everything ... for nothing. So keep your opinions to yourself.||”|
— Castiel to Dean for doubting his plan
in Good God, Y'all
Looking for a way to find God, Castiel approached Dean for help in capturing and interrogating Raphael on God's location. After Castiel retrieved Holy Oil for the trap, Dean took him to a strip club after learning that Castiel was a virgin so he wouldn't die as one. Castiel was clearly nervous in the strip club and ended up angering the stripper by telling her that her father left because he hated his job, not her.
Castiel and Dean later succeeded in trapping Raphael, who told them God was dead but Castiel rejected this by bringing up his resurrection, to which Raphael stated Lucifer could have did it. Though Castiel denied this and decided to leave, as Raphael demanded his release and threatened to find them, but Castiel left him where he was, telling him that "Maybe one day, but today you're my little bitch" a comment that Dean agrees with.
In The Song Remains the Same, when Anna returns and tries to make contact with Sam, Castiel meets her instead. He had convinced the Winchesters to stay behind because he did not trust her. After Anna revealed her plans, Castiel refused to let her kill Sam by declaring him as his friend and threatened to kill her if she still tried, regardless of their history. Anna remarked on his change in loyalty, as he commented that it may have came to late but Anna still had a plan and left.
Castiel did not sense Anna's presence and realized she went back in time to 1978 to kill John and Mary Winchester so that Sam and Dean wouldn't be born to break the first and final seals. Castiel tried to go after her alone but was encouraged by the Winchesters to take them back in time to stop her, which he reluctantly agrees too.
The trio traveled to the past but the journey caused Castiel pain as the brothers let him rest in a motel as they went after Anna. At the end, Anna is killed by Michael who sends the brothers back to their time while Castiel regained enough power to return to the future. Once he touches down, he is again helped by Sam and Dean who lay him down on the bed. While Castiel lays down, Dean counts him, himself and Sam as Team Free Will.
In The End, Castiel contacts from a cellphone and tries to retrieve him but a tired Dean sets a time for him to get him. Zachariah discovered Dean's location and sent him to an alternate post-Apocalyptic future in which Lucifer had ravaged the world with the Croatoan Virus.Castiel is the only angel still fighting for the sake of humanity. He had lost his powers but joined Future Dean's resistance movement against Lucifer, he also could still tell Dean was from the past when meeting him despite acting in self-indulgence with women of the army. He presumably died in the final confrontation against Lucifer. After Dean is returned to the main world, Zachariah tries to properly secure Dean as Michael's vessel but Castiel was able to rescue Dean from his brother by teleporting him away. Castiel remarks that he and Dean set a point and that he retrieved him exactly. Dean told him to never change before he called Sam.
After Sam and Dean were kidnapped by the Trickster, Castiel searched for them and came to their rescue but was stopped by the trickster who teleported him away. A battered Castiel later made his way back long enough to warn the Winchesters that the Trickster was too powerful to be a trickster though before he could elaborate, he was flung aside. The Trickster himself then appeared, bound Castiel's mouth as he greeted Castiel amicably and effortlessly banished him. The Trickster's familiarity with him along with Castiel's information and various clues caused Sam and Dean to realize the Trickster was actually an angel. Their theory is confirmed as the trickster is revealed to be the Archangel Gabriel after they trapped him in a Holy fire circle, Dean forced him to bring Castiel back from wherever he'd put him. Once he returned, Castiel assured Dean that he was okay before he greeted his brother coldly, revealing he figured out the latter's identity too. Gabriel returned this sentiment by taunting Castiel about his pointless search for their father. Castiel watched the end of Sam and Dean's confrontation with Gabriel, before Dean releases Gabriel from the ring of fire.
When Sam, Dean, Ellen Harvelle and Jo Harvelle went after Lucifer, Castiel joined them, drinking shots with Ellen before they took off and taking a picture with the group. In Carthage, Castiel separated from the group to follow a Reaper and was captured and held in Holy Fire by Lucifer who tried to convince the angel to join him. Castiel refused and was held captive by Meg who taunted him. However, Castiel managed to loosen a pipe and use it to knock Meg into the circle where he tried to smite her only to find he'd lost that power. Castiel used Meg's body as a bridge to escape and teleported Sam and Dean, the only other survivors of the failed mission, away from Lucifer.
Castiel later assisted Sam and Dean in tracking down a cupid, who they believed was responsible for the death of a couple. When the cupid was heart-broken by their accusations, Castiel was tasked with calming him down as his brother pleaded to him to read his mind and was proven innocent. The three of them then discovered that Famine was behind the deaths. Famine's presence caused Castiel to hunger for red meat.
When the brothers were ambushed and killed by two hunters furious with them for causing the Apocalypse, Castiel warned the brothers that Zachariah was looking for them in Heaven and they should attempt to contact an angel named Joshua, who was rumored to speak to God. After talking with Joshua, it was confirmed that God was the one who resurrected Castiel not Lucifer as Raphael suggested.
When the brothers returned from death, Sam revealed that God wanted nothing to do with them, causing Castiel to abandon his belief in God and return Dean's amulet, stating that it was worthless. He fell into a depression and drank heavily, but sobered up in time to help defeat the Whore of Babylon.
In Point of No Return, Castiel helped Sam bring Dean to Bobby's house where was angry with Dean's decision to say yes to Michael before he sensed something. He went to another area and fought three angels before bringing back the Winchester's half-brother Adam who has been resurrect. Castiel carved Enochian sigil on Adam's ribs to prevent the angels from finding him, causing him to wake up. When Adam mentioned, he was brought as a substitute vessel for Michael instead of Dean, Castiel confirmed its possible since Adam is of the Winchester bloodline. Later on, he and Sam lock Dean away in the panic room to prevent his escape. At one point, Dean banished Castiel but the latter returned after sensing a man praying to the angels allowing Cass to locate Dean and he angrily shouted he had sacrificed everything to follow Dean as he believed in him. Castiel proceeded to beat Dean up out of pure rage before calming himself and taking him to Bobby. When Sam and Dean go to rescue their brother Adam Milligan who had been taken by Zachariah, Castiel carved an angel banishing sigil into his chest and uses it to banish four angels and himself after showing his lack of faith in Dean by saying at least he won't have to see Dean fail. However, Dean ultimately doesn't go through with saying yes to Michael and kills Zachariah instead though Michael takes Adam.
In Two Minutes to Midnight, Castiel returned powerless, apparently from the banishing sigil. He apologizes to Dean for doubting him and comes to their aid when confronting Pestilence, stating to the horseman that he used the bus to get there.
In his weakened state, Pestilence easily brings Castiel down, but he possesses just a "speck" of his angelic self left, just enough to resist Pestilence's power long enough to cut off his ring and defeat him. Castiel later joins Bobby and Sam in an assault on Niveus to stop the Croatoan Virus, bemoaning his lack of power. Despite this, Castiel does a good job, stopping a truck loaded with the virus from leaving and killing a zombie with a shotgun (which he remarks is actually useful) saving Sam's life.
In Swan Song, now almost completely human, Castiel accompanies Bobby, Dean and Sam to Detroit where Sam will say Yes to Lucifer as part of their plan. Castiel awkwardly says goodbye to Sam and tries to reassure him that they will be okay, but is bad at it. When Sam fails to overpower Lucifer, Castiel loses hope and suggests they get drunk and wait for the end to come. Dean refuses to give up and manages to get Castiel and Bobby to help him. In the final confrontation, when Michael (in the vessel of Adam) was about to fight Lucifer (in the vessel of Sam) Dean intervened saying he wished to speak with Sam. This prompted Michael to try and remove Dean, however, before he could respond Castiel teleported into the field with Bobby and insulted his brother as he threw a Molotov of holy fire at Michael, sending him back to Heaven for a brief time.
Lucifer turned to Castiel, furious by the fact that Castiel harmed his brother. Castiel for the first time showed fear when he realized that he had enraged Lucifer, who snapped his fingers and caused Castiel to explode. Shortly after the battle between Dean and Lucifer where Sam was able to retake control and throw both himself and Michael into the Pit, Castiel was resurrected by God and appeared to Dean telling him he was brought back new and improved with his angelic powers restored and upgraded, allowing him to restore Dean's broken bones and bring Bobby back to life. Castiel, now a Seraph, said that he needed to return to Heaven to restore order to the anarchy that will follow Michael's departure.
|“||With Michael in the cage, I'm sure it's total anarchy up there. [...] I don't know what God wants. I don't know if he'll even return. It just ... seems like the right thing to do.||”|
— Castiel deciding to restore order in Heaven
in Swan Song
Return to HeavenEdit
|“||No one leads us anymore. We're all free to make our own choices and choose our own fates. [...] God wants you to have freedom.||”|
— Castiel to angels during his return
in The Man Who Would Be King
After the Apocalypse was averted, Castiel managed to save Sam and pull him out of Lucifer's Cage with his enhanced powers, though didn't know at the time he hadn't brought him back with his soul. Castiel visited his favorite part of Heaven – a Tuesday afternoon of a 40-year old autistic man who drowned in a bathtub in 1953 – where other angels awaited him. Castiel preached freedom to them instead of having a leader, but they don't know how. Castiel struggled in Heaven his first few weeks back as he tried to get the angels to embrace freedom, later likening it to "teaching poetry to fish." During this time, Castiel was confronted by Raphael. Castel and Raphael clash over their different ideologies for Heaven – Castiel with his emphasis on freedom and peace while Raphael wants to free Michael and Lucifer from the cage to start the Apocalypse again. Raphael tries to get Castiel to bow to him, but Castiel refuses.
Due to his defiance, Castiel is no match for him and threatened to submit or suffer. Castiel tries to get help from Dean, but seeing Dean retired makes Castiel rethink this. Crowley suddenly approaches Castiel, proposing him a deal to have him grow strong enough to defeat Raphael by collecting monster souls if he lets Crowley have access to Purgatory. Crowley also suggests he lead Heaven since he is the only angel to be resurrected by God, though this would start a civil war. Castiel refuses all propositions, but begins to consider it when Crowley twists it as either his option or the apocalypse all over again. Castiel reluctantly agrees to the deal. Crowley resurrects Samuel Campbell (the Winchester's grandfather) to help them find Purgatory while giving Castiel a thousands of souls from Hell to power him up against Raphael for the time being.
Castiel, powered up with souls, challenges Raphael and divides Heaven between him and the archangel. Castiel also cuts contact off from Sam, who repeatedly prayed to him many times for explanations on getting out of the cage.
|“||There will be no Apocalypse. And let it be known – you're either with Raphael or with me.||”|
— Castiel starts the civil war
in The Man Who Would Be King
|“||Raphael and his followers, they want him to rule Heaven. I -- and many others -- the last thing we want is to let him take over. It would be catastrophic. [..] Whoever has the weapon wins the war.||”|
— Castiel's ongoing battle with Raphael
in The Third Man
Castiel struggles with the civil war in Heaven against Raphael. When Sam and Dean found out plagues were unleashed upon the Earth, they called Castiel for help. Castiel didn't answer for Sam but showed up for Dean and told them the Angelic Weapons were stolen from Heaven. Castiel withholds his involvement with Sam's return by claiming to not know what or whom brought Sam out of his cage.
During their investigation, they find out that an Angel has been moonlighting as a crossroads demon. To locate the angel's name, Castiel performed a ritual to find the angel that bought the soul. When Castiel learned it was his old friend, Balthazar, an angel follower of Raphael showed up and attacked Castiel. Castiel managed to defend himself and let the angel get away, but the angel knew that Balthazar was selling pieces of the Staff of Moses. So Castiel, Dean and Sam try to find Balthazar first, and when they do, Balthazar admitted that he stole the weapons from Heaven and that he want to live in freedom. When Balthazar disappears, Castiel is confronted by angels who want to kill him. Castiel asked them to join him, but they refused and Castiel killed them. Afterwards, Raphael showed up and told him that they were his followers and attacked Castiel before defeating him. Raphael voiced his doubt of God bringing him back again but just as he was about to kill Castiel, Balthazar showed up and used the weapons from Heaven to destroy Raphael's vessel. Eventually, Sam and Dean showed up and were able to trap Balthazar in a circle of holy oil, but Castiel lets Balthazar go after they force him to let go of his hold on the soul with Castiel's reason being that he owed Balthazar his life.
Dean becomes more and more disturbed by Sam's behavior, and prays for Castiel's help. Castiel doesn't respond until Dean calls him about a possible loose nuke, much to Dean's aggravation. Castiel apologizes, but reassures Dean on his theory that Sam is not Lucifer, explaining that all angels would feel his presence if Lucifer was free. Castiel also states he doesn't know what's wrong with Sam, but he promises to make inquiries. Dean calls on Castiel once he has Sam unconscious, and asks for him to diagnose Sam. Castiel informs both brothers that physically, Sam is perfectly healthy, but his soul is missing. He guesses that Sam's soul is still in the cage with Michael and Lucifer. When Sam goes with Samuel as his only lead, Castiel follows Sam and Dean to the Campbell Compound. He meets the Winchesters' grandfather Samuel Campbell who is amazed to see him before he checks if Samuel has a soul or not, which he does. However, before he can do any more to help, he states he needs to return to Heaven, but reassures Sam and Dean that their problems "always come first", and will keep in touch.
Castiel is later called on for assistance by Sam, who tricks him into leaving Heaven by saying he and Dean have found the Ark of the Covenant. Sam tries to coerce Castiel into joining them along with the demon Meg and her minions to confront Crowley, but fails as Castiel knows Sam can't harm him. However, recognizing that Sam really does need help, Castiel decides to help anyway. Castiel tries to track down Crowley by means of a ritual, which leads them nowhere. When the group is caught by Samuel as they search through his quarters, Dean asks for the angel to leave back to their motel.
Sometime later, while Sam and Dean are looking through records trying to find Crowley, Castiel is confounded by watching porn, which he states just happened to be on the TV. He creates an awkward moment with the Winchesters, even creeping Samuel out upon arriving at their motel. He leaves with the group after Samuel gives them the location of Crowley's prison. Before leaving for the prison, Castiel suggests to Dean that he doesn't think restoring Sam's soul is wise. He supports his statement with the fact that his soul has been locked in the cage with Michael and Lucifer for more than a year, and they have been doing nothing other than taking their frustrations out on Sam. He theorizes that if they try to force the damaged, tortured soul back into Sam, and if they fail to deal with the problems, then Sam will suffer horrifically.
The group then leaves for the prison, and Castiel finds a back entrance inside. Shortly after, hell-hounds come after the party. Meg distracts Castiel by kissing him, and steals his angelic blade. Castiel, surprisingly, responds to this by kissing her back, stating he learned that from the porn he was watching earlier. The boys then run off while Meg holds off the hell-hounds with the angel blade. Later, Castiel is banished by a blood sigil cast by a treacherous Samuel, while the Winchesters are taken captive.
While Crowley has the boys pinned to the wall, Castiel reappears, carrying a large bag. After Crowley taunts him about his losing war against Raphael, Castiel reveals that the bag contains his salvaged bones. The angel asks the King of Hell one last time if he can restore Sam's soul or not. Crowley says he cannot, and Castiel proceeds to burn his bones, seemingly turning him to ash. However, it's later revealed Castiel deceived the Winchesters considering his deal with Crowley and the bones were the wrong ones.
A short moment later, outside the prison, Castiel later admits that he is on the losing side of the civil war in Heaven, and expresses disappointment as he wishes much of the time that circumstances were different as he prefers being on Earth with Sam and Dean. Dean then reassures the angel that they will help in whatever way they can, and that the brothers are his friends. Castiel then turns to Sam, and reassures him that they will find another way to get his soul back. Sam then asks him to dispose of the monsters that still remain inside the prison, to which Castiel presumably leaves to do so.
|“||It's not going well for me upstairs [...] I wish circumstance were different. Much of the time I'd rather be here.||”|
— Castiel to Sam and Dean
in Caged Heat
After Sam gets his soul back, Castiel comes to check up on him, and tells Dean that he doesn't think Sam is ever going to wake up while criticizing him for not heeding his warning about the soul. A few hours later, Sam wakes up and reunites with his brother while happy to hear Cass is alive since he recalled Lucifer killing him. Later on, Sam, now with his soul again, calls Cass and Castiel comes. He tells Sam that he is glad to see him well, despite everything, nearly hugging him. Sam tells Castiel he would hug Castiel, but it would be awkward. Sam goes on to talk about how its been a crazy year and how he just talked to Bobby about it. Castiel tells Sam he's surprised Sam even survived. Castiel asks Sam how it feels as Sam looks confused. Castiel explains, "to have your soul back". Sam tricks an unaware Castiel into telling him the truth while learning about his soulless year.
In My Heart Will Go On, Castiel saves Sam and Dean from Fate, when she tries to get her revenge for stopping the apocalypse. He tells the brothers if they want to live, they need to kill Fate. So Sam and Dean draw Fate out and just as they face their death, time freezes. Castiel is confronted by the Fate Atropos who reveals the real reason why Balthazar saved the Titanic was because Castiel ordered Balthazar to do it for the souls. She threatens to kill Sam and Dean unless Castiel fixes history. Choosing his friends safety over the war, Castiel orders the creeping Balthazar to refrain from killing Atropos and to right history.
|“||You're the ones that taught me that you can make your own destiny. You don't have to be ruled by fate. You can choose freedom. I still believe that's something worth fighting for. I just wanted you to understand that.||”|
— Castiel to Sam and Dean
in My Heart Will Go On
Afterwards, Castiel tells Sam and Dean that he made sure they kept their memories of the alternate timeline as he wanted them to know of the choice he made. He lies that of Balthazar's motives on the matter and leaves the area.
In Frontierland, Cass returns to send Sam and Dean back to the Wild West so the brothers could acquire ashes of the phoenix, the one thing that could kill the mother of all. He tells Sam and Dean they have only 24 hours, after that he will no longer be able to find them. During the time the boys are in the Wild West, Castiel's lieutenant, Rachel, confronts him about his side dealings Castiel is doing to win the war. This leads to a duel between the two, and Castiel emerges the winner and wounded. He soon heads to Bobby's, draws a symbol in his blood and passes out. As time grows short, Castiel re-awakens, but is very weak and low on power. In order to "power up" he tells Bobby he needs to touch Bobby's soul. Once powered up, Castiel brings the boys back.
Now with the ashes, the hunt for Eve is on. Castiel comes to Sam and Dean asking for Eve's location, but they too are unsuccessful. Sam suggests that they find a good monster who would be willing to give them Eve's location. Castiel finds and brings Lenore, who gives them Eve's location, in exchange for her death. Sam is hesitant, but Castiel brings Lenore her end. This action makes Sam and Dean concerned about Castiel and his circumstances. Once they arrive in Oregon, Castiel discovers he can't use his powers, and is now powerless, thanks to Eve. Castiel is able to torture Eve's location out of a Jefferson Starship, but is captured by her monsters. After Dean kills Eve, Castiel's powers return and he slays the Jefferson Starships with a blast of white light. Castiel is later revealed to be working with Crowley after the Winchesters' encounter with Eve.
The truth finally comes out in The Man Who Would Be King, Castiel recounts history from his point of view and how the Winchesters inspired him. Castiel is shown clearly conflicted over his partnership with Crowley, but agrees to keep the Winchesters from finding him. Castiel also begins to notice that Sam, Dean, and Bobby are getting suspicious of Castiel and believe he is working with Crowley, strengthening his guilt. After catching a lead of a demon called Ellsworth and Crowley's other higher up demons, Castiel goes and smites them before Sam and Dean can get information. He justifies this as protecting them from Crowley, but also wonders if it's to protect himself. He reflects on his return to Heaven after the Apocalypse, the conflict between him and Raphael that was sprung up, and his fateful deal with Crowley.
Castiel tries to minimize contact with Sam and Dean, knowing they were on to him and he could give them no honest answers. However, when Crowley sends his best demons to fight them, Castiel shows up to save them. Although Castiel managed to keep the secret for a while, he slipped up with information he got from spying on them. Castiel is furious with Crowley's attempt to kill Bobby, Sam and Dean, warning him that if anything happened to them he would call off their deal and kill him himself.
Later the boys trapped him in a ring of holy fire and confront him about his betrayal. He pleas to them to understand his plight, even revealing to them that he was really the one who rescued Sam from Lucifer's Cage not Crowley. However, he is accused by Sam of bringing him back soulless intentionally which he quickly denies. When demons come, Castiel tells them to run and they leave him in the ring of holy fire. Crowley comes in and saves him. Castiel leaves, and comes to Dean, trying to explain the situation. Castiel tells Dean that he did this for Dean but Dean does not want it this way. Castiel responds that Dean can't stop him and says he's sorry and disappears. Castiel tells his father God all of this when he's by himself, praying for a sign if he's making the right choice, but gets no answer.
|“||So that's everything. I believe it's what you would call ... a tragedy from a human perspective. [...] That's why I'm asking you, Father. One last time. Am I doing the right thing? Am I on the right path? You have to tell me. You have to give me ... a sign. Give me a sign. Because if you don't ... I'm gonna ju- I'm gonna do whatever I ... whatever I must.||”|
— Castiel praying for answers
in The Man Who Would Be King
In Let It Bleed, Castiel has taken one of the Campbell diaries, and is investigating an incident in which H.P. Lovecraft opened a portal to another world. Sam prays for him, telling Cass that Lisa and Ben have been kidnapped by Crowley, and asks for help. Castiel listens unseen, and does not answer, but goes to confront Crowley. He insists that the demon not harm Lisa and Ben, but Crowley refuses to make such a promise. Balthazar later calls him. He asks Cass if he is planning on opening the door to Purgatory; Cass lies that he is not, but Balthazar is not fooled. Castiel asks if he is with him, or not. Balthazar says he is, and Castiel goes to Dean, arriving just in time to save him from a demon. He apologizes for Lisa and Ben, revealing that he did not know Crowley's plan. Dean is skeptical, and angry. Castiel asks him again to support his decision to tap the souls in Purgatory. He pleads with him that he has always done what the brothers needed him to, asking little in return. Cass asks them to trust in him, and promises to bring him his family afterward. Dean is unwilling, and Castiel leaves. After Dean and Sam rescue Lisa, Castiel comes to the hospital where the gravely injured Lisa is not expected to survive. He apologizes again, but Dean is not forgiving. Castiel says that he did not come for Dean, then places a hand on Lisa's forehead, healing her. Both Dean and Cass acknowledge that this does not change their situation, but Dean asks for an additional favor. Castiel removes all Lisa and Ben's memories of Dean. Later Castiel finds and takes Dr. Visyak, the creature he needs to open Purgatory.
|“||I thought that you said we were like family. Well, I think that too. Shouldn't trust run both ways? [...] Dean, I do everything that you ask. I always come when you call and I am your friend. Still, despite your lack of faith in me and now your threats, I just saved you yet again. Has anyone but your closest kin ever done more for you?||”|
— Castiel's appeal to Dean
in Let It Bleed
In The Man Who Knew Too Much, Castiel and Crowley torture Dr. Visyak until they obtain what they need to open Purgatory. She escapes and contacts Bobby and the Winchesters, telling her story before dying in an alley from her injuries. Castiel comes to the three hunters, who are outraged. Dean tries to argue with him again, but Cass cuts him off, saying he no longer cares about Dean's opinion. He then touches Sam's head, breaking the mental wall, and promising to repair him as long as Dean stops the opposition.Castiel meets with Crowley, who has assembled the necessary ingredients. The angel wants to renegotiate their deal. He will not give Crowley the souls, so Crowley can either flee or die. The demon leaves Castiel with the blood for the ritual. Later, Castiel confronts Balthazar. He says that Dean is coming, and someone among them is a traitor. Balthazar asks him who it is, and Castiel lies that he does not know, and wants Balthazar to investigate. While the other angel is distracted, Castiel stabs and kills him. Just before the ritual is meant to begin, a cloud of demons descends around the building, and Crowley appears. Castiel tries to kill him, but cannot. He has a new partner in Raphael. Castiel is surprised at the partnership with their differing goals, but both seem to think they have taken the best course available. They demand the blood; Castiel throws them a jar and leaves. Crowley conducts the ritual, and though Bobby and Dean try to interrupt, completes it.
Nothing happens and Castiel reappears. Crowley realizes that he switched the blood, and conducted his own ritual. Castiel displays his power briefly in a flash of energy. Crowley, realizing the game is up for the time being, wisely disappears, and Raphael asks for mercy.
But Castiel is not in a forgiving mood. He snaps his fingers, obliterating Raphael to pieces in mere seconds. He turns to Dean and Bobby. He was right, he says, and he did save them. Dean nervously agrees, then suggests that Castiel should return the souls, and disarm himself. Castiel says he has Raphael's followers to deal with. Dean is worried, and reminds Castiel that he is family, and he doesn't want to lose him. Castiel says that he has no family anymore; he will not give up the souls.
Using that moment, Sam stabs him from behind with an angel sword, but nothing happens. Castiel greets him, then says the sword will not work because he is not an angel anymore. He says that he is their God, and that they must venerate him, or be destroyed. As he says those words, Dean, Sam and Bobby look on in horror, realizing with shock that their former ally and friend has become a power-hungry angel who believes that he is God.
|“||You doubted me. Fought against me. But I was right all along. [...] You're not my family, Dean. I have no family. [...] I'm your new God. A better one. So you will bow down unto me, your Lord. Or I shall destroy you.||”|
in The Man Who Knew Too Much
|“||If you followed Raphael, if you stood against me, punishment is certain. There is no where for you to hide. The rest of you ... our father left a long time ago, and that was hard. I thought the answer was free will. But I understand now. You need a firm hand. You need a father. And I am your father now. [...] It is a new day, on Earth and in Heaven. Rejoice.||”|
— Castiel as God
in Meet the New Boss
Castiel waits for Sam, Dean, and Bobby to show their respects. Bobby goes to his knees, and motions for Sam and Dean to do the same. Dean and Sam begin to kneel, but Castiel stops him, and orders Bobby to stand, saying that there is no point if they do not mean what they do. Castiel observes, without turning to look, that Sam is not doing well. Dean reminds Cass that the former angel promised to fix Sam when it was over. Castiel cuts him off; his promise was contingent on Dean not opposing him further, and oppose him Dean did. Castiel tells them he has no need to kill them, though he no longer has any regard for them, and will let them live if they do not plot against him.
Castiel sets out to right the wrongs he sees. He destroys Raphael's followers in Heaven, vaporizing thousands of angels, and tells the survivors that he no longer thinks free will is what Heaven needs. Instead, he will give them a firm hand. He appears in a church, reveals his identity, and smites a hypocritical preacher. He leaves an image of himself in the stained glass as he departs, and accidentally burns a pew as welts appear on his hand.
He finds Crowley hiding in a RV, and tells him that he may retain his position as King of Hell, but that Castiel will choose which souls he receives. He claims that he would have destroyed Hell completely, but he needed it to threaten his enemies, and maintain Michael and Lucifer. It is unknown if he actually had the power to destroy Hell, or he was over his head with all the souls inside him. He leaves after looking at yet more open places on his skin. He gives money to a blind man on the street, and heals the man for his faith. The man is grateful, but surprised when his first sight is of Castiel's blistering face. At a nearby bathroom, he looks in the mirror and stares at the blisters covering his face and hands. His stomach begins to bulge and contort as the Leviathans demand to be let out, whispering to him as he looks down in horror, mumbling "No."
Sam, Dean, and Bobby summon Crowley, who reluctantly gives them a spell to bind Death. They work it, and an irritated Death appears, followed shortly by Castiel. Dean orders Death to kill 'god'. Death says he sees only a mutated angel, one whose vessel is disintegrating. Castiel, sounding uncertain, says he will heal himself when his works are complete. Death replies that Castiel swallowed Leviathans when he emptied Purgatory, not just souls, and that is the danger. Castiel frees Death from Dean's binding spell.
Castiel leaves. At a political election office campaigning for a senator of whom Castiel disapproves, he is stopped by one of her aides. Castiel asks the man to see that he is a good god, that he means the best for his children. He awakes some time later in a pool of blood on the floor. He has slaughtered the entire office. At Bobby's place, Sam prays for Castiel to reconsider and give up the souls. A few minutes later Castiel appears, disheveled, bloody, and looking ill. He says he needs their help.
He listens to Sam's call and agrees to put all the souls back in Purgatory. Before the opening of the door, he expresses regret at what he has done and wishes that he could have restored Sam back to normal, and promised to do so if he survived. After he lets out all the souls, Cass passes out but wakes up. He automatically begins to contort and struggle as the Leviathans had held on to his body are trying to take over.
|“||I feel regret, about you and what I did to Sam [..] If there was time, if I was strong enough, I'd--I'd fix him now. I just wanted to make amends before I died.||”|
— Castiel to Dean
in Meet the New Boss
Castiel is soon overpowered by the Leviathan who in turn take control of him, presumably taking him far away. They begin by throwing Dean and Bobby against a wall before saying that they're going to have fun now. Soon after flinging them, his vessel begins to ooze black blood, and Dean smugly points out that the vessel can't contain the power of the Leviathans. They leave saying they will be back for Dean. The Leviathans are able to guide Castiel's vessel to a water reserve and the vessel explodes in a whirlpool leaving the Leviathans to escape into the water. Later, his trenchcoat is found, Dean folds it up and takes it with him.
It was later revealed in Slash Fiction that the Leviathans learned of Sam and Dean's aliases from Castiel's mind before they escaped from inside him.
After being killed by the Leviathans, Castiel was resurrected by God and awoke with no memory of what he was or his past. He was found by a religious woman named Daphne, who declared "God wanted her to find him". Castiel named himself Emmanuel and lived with Daphne, his wife as a healer. Dean hears word of his healings and is shocked to see Castiel alive, but refrains from telling him the truth of who he is and tells him to heal Sam, who had been driven insane by his hallucinations of Lucifer. Castiel figures out he has a past with Dean and Meg, but fully regains his memories after smiting demons guarding Sam's ward. Castiel is angry and ashamed of himself for all the death he had caused and nearly leaves out of guilt, but Dean convinces him he can still fix things.
|“|| Castiel: "Do you have any idea the death toll in Heaven? On Earth? We didn't part friends, Dean. [...] I deserved to die. Now I can't possibly fix it ... so why did I even walk out of that river?"|
Dean: "Maybe to fix it.
— Castiel after regaining his memories
in The Born-Again Identity
Motivated by Dean, Castiel apologizes to Sam for breaking down his wall and attempts to rebuilt it only to discover it was completely destroyed with Sam's collapsing mind. In one last effort to redeem himself, Castiel shifted the hallucinations of Lucifer from Sam's mind to his own in order to save him. Castiel then looked on in horror as he saw the hallucinations of Lucifer Sam seems better than ever and regains his sanity, though at the cost of Castiel's own. He is admitted to psychiatric ward. Meg becomes a nurse through partially out of a deal with Dean to look after him.
In Reading Is Fundamental, Castiel awakens from a coma when The Word of God is released from the clay containing it, but is still insane with an eccentric personality. Castiel explains what the Word is, but is unable to give Dean the answers he seeks and Dean is still angry with him for what he did to Sam. Castiel no longer fights anymore and tries to "avoid conflict". While talking to Dean, Castiel senses other angels and finds Hester and Inias, two angels from his former garrison. While Inias is happy to see him, Hester is furious due to the damage he caused. Before things can degenerate too far, Dean banishes all three angels. Castiel later meets up with the group on the road to Rufus's cabin and helps angel-proof it. In a conversation with Sam, Castiel reveals he's been more at peace ever since he took on Sam's memories of Hell and liked his being insane than being guilty and sane.
|“||It's funny. I was- I was done for too. The weight of all my mistakes, all those lives and souls lost ... I-I couldn't take it either. I was ... lost until I took on your pain. It's strange to think that helped, but ...||”|
— Castiel's apparent peace with his insanity
in Reading Is Fundamental
When Meg returns, he confirms her story that she killed other demons, but warns that she has drawn the attention of the angels. Hester and Inias arrive with two other angels, but in his mental state, Castiel is now a pacifist and refuses to fight, even to save his own life. Castiel is nearly killed by Hester, but Meg kills her and saves him. Afterwards, Inias offers Castiel the chance to return to Heaven, but he chooses not to as he no longer feels like he belongs there.
Sam and Dean discover from the translation of The Word of God that they need the blood of a Fallen Angel for the weapon that can kill Leviathans and Castiel happily gives them his blood telling them "always happy to bleed for the Winchesters." Castiel then disappears, not sure where he's going next, something he finds amazing.
In Survival of the Fittest, Castiel has Meg bring him to the Winchesters after learning that the Leviathans have killed all of his garrison. Crowley arrives and is furious to see Castiel alive, but leaves him alone as he is insane and he doesn't want to pick a fight with a crazy person. He also leaves Meg alone when Castiel gets defensive of her, telling Sam and Dean that Castiel is vital to defeating the Leviathans. Castiel denies any knowledge of what he's talking about however. After finding out that the Leviathan leader Dick Roman has made multiple copies of himself, Dean turns to Castiel for the help Crowley said he could give them, but he refuses to do anything due to his new pacifism and fear of messing up again. Meg reveals that due to being the Leviathans original vessel, he possesses the ability to tell them apart and could identify the real Dick Roman.
|“||I can't help. You understand? I can't. I destroyed ... everything and I will destroy everything again. Can we please just leave it at that?||”|
— Castiel refusing to help
in Survival of the Fittest
After watching Bobby being put to rest, Castiel takes Dean to retrieve the Impala and explains his reasoning for refusing: he feels that he is bad luck and will cause more harm than good if he gets involved again. Dean finally forgives him for what he did to Sam and Castiel agrees to help. The next day, while Sam rescues Kevin Tran, Castiel and Dean make their way through SucroCorp looking for the real Dick.
|“|| Castiel: "If we attack Dick and fail, then you and Sam die heroically, correct? [...] Or at best, I die trying to fix my own stupid mistake. Or I don't die. I'm brought back again. I see now. It's a punishment resurrection. It gets worse every time. [...] I'm not good luck, Dean.|
Dean: "Yeah, but you know what? Bottom of the ninth, and you're the only guy left on the bench. Sorry, but I'd rather have you, cursed or not. And anyway, nut up, alright? We're all cursed. I seem like good luck to you?"
Castiel: "Well, I don't want to make you uncomfortable ... but I detect a note of forgiveness. [...] I'll go with you. And I'll try my best."
— Castiel deciding to fight with Dean
in Survival of the Fittest
Soon enough, they confront Dick. Castiel tries to take Dick on, but is thrown into a wall and easily defeated. This allows Dean to stab Dick with the weapon, but it doesn't work. This causes him to lower his guard as Castiel restrains Dick from behind while Dean stabs him through the neck with the real weapon, killing him. However, Dick pulsates a strange aura and after he explodes, there is no sign of Dean and Castiel.
When Dean wakes up, Castiel, with his original personality apparently back, tells him that they are in Purgatory and are more likely to die then get out. He then disappears, leaving Dean alone and surrounded by monsters.
Year in PurgatoryEdit
|“||I am an angel in a land of abominations. There have been things hunting from the moment I arrived. [...] They're Leviathan. I have a price on my head and have been trying to stay one step ahead of them. To keep them away from you. That's why I ran. Just leave me, please.||”|
— Castiel upon reuniting with Dean
in What's Up, Tiger Mommy?
Some time passes and there is still no sign of Castiel. Dean obsessively tries to find him, even teaming up with a vampire named Benny who knew of a portal that would get them out (which could only be done by a human). Eventually, after scoping out Purgatory and going through several monsters, Dean finds him alive near a stream. Castiel confirms he's as sane as he could be targeted by monsters and the friends reunite.
Dean is eager to leave Purgatory with Castiel, though Benny casts suspicion on him by his sudden disappearance earlier on. Castiel admits he did run away and leave Dean alone, but it was only to protect him. The Leviathans wanted him destroyed more than anything because of his actions and he believed leaving Dean would make the Leviathans focus on him rather than on Dean. Because of this, Castiel requests to stay in Purgatory, but Dean tells him there is hope and has Benny inform him of the portal to escape, though he is unsure if it will work for Castiel. Despite this, Dean refuses to leave without him as Castiel understands.
Castiel travels with Dean and Benny, helping them kill more monsters although at the same time attracting more. While Dean doesn't care about this and is angry about Benny at the idea of leaving Castiel, Castiel agrees with Benny and sees himself as only causing trouble. Benny and Castiel aren't sure that he could cross through the portal, being an angel, but Dean adamantly insists. Soon the group is attacked by Leviathans. Castiel tries to lure them away, but is overwhelmed and nearly killed by one. Benny saves him.
In the final stretch, when Benny's soul is stored safely inside Dean's arm from the spell and they are moments away from the portal, Dean and Castiel are attacked by Leviathans. At the last minute, as Dean reaches out for Castiel, Castiel lets go of him and Dean is transported to Earth without him. Castiel watches, having decided to stay for further punishment for his mistakes.
|“||Nothing you could've done would've saved me, because I didn't want to be saved. [...] It's where I belonged. I needed to do penance. After the things I did on Earth and in Heaven, I didn't deserve to be out. And I saw that clearly when I was there. I ... planned to stay all along. I just didn't know how to tell you. You can't save everyone, my friend ... though you try.||”|
— Castiel to Dean on why he stayed in Purgatory
in A Little Slice of Kevin
In We Need To Talk About Kevin, Dean and Sam mention Castiel after Dean returns to Earth with Benny. Dean is vague about Castiel's fate, only mentioning that it got hairy near the end and Castiel "let go." While Dean didn't elaborate, remembering this clearly affected him greatly.
Dean had flashbacks of Castiel in What's Up, Tiger Mommy?, remembering finding him and his promise for Castiel to leave Purgatory with both him and Benny. Dean is clearly upset remembering all this and has another flashback where Castiel was struggling to hold onto his arm, while it is unclear what the scenario is, Castiel shouted Dean's name as they are pulled apart.
|“||You know, there are some in Heaven who still believe, despite his mistakes, that Castiel's heart was always in the right place. [...] I think 'too much heart' was always Castiel's problem.||”|
— Samandriel to Dean about Castiel
in What's Up, Tiger Mommy?
Castiel finally escapes Purgatory in A Little Slice of Kevin. He claims he could not remember how he escaped, a story not received well by a doubtful Dean. Castiel aids the Winchesters and Mrs. Tran in saving Kevin and retrieving the tablet from Crowley. He displays much of his previous abilities, but is weakened quickly now. Castiel saves Kevin and confronts Crowley with his angel blade. Crowley pulls out one of his own and they face off. Castiel displays his wings and goes to smite Crowley who finally retreats, but tries to take the tablet. Castiel smashes it in half and Crowley only gets away with one part. Afterwards. when Dean admits he blames himself for leaving Castiel behind in Purgatory, Castiel tells him he wanted to be left behind in Purgatory as a form of penance.
Moments after, Castiel finds himself in Heaven with an angel named Naomi. It's revealed that his escape was orchestrated by her, claiming many angels in the process. Castiel casually reveals information about the Winchesters and the tablet under control of Naomi. He is sent back to earth without any memory of the meeting and the orders to report into her every so often. Castiel aligns himself with Sam and Dean in searching for the second half of the tablet and fixes Kevin's cut-off finger.
Castiel formally took up the mantle of being a hunter in Hunteri Heroici. Dean and Sam were skeptical at first, but both eventually allowed the seraph to join them in a case that Castiel himself found. The Winchesters also guided Castiel on how to pose and act as an effective hunter. Castiel also admits that he fears returning to Heaven: he fears that when he returns and learns just how bad he made it, he will kill himself out of regret. While Castiel is awkward and clumsy at being a hunter, he proves very helpful in solving the case, using his powers to bring Sam into the mind of Fred Jones, a man who is living inside his own mind as it is easier than having to live with the real world. Sam gives Fred a speech about living in a dream world but facing up to your past eventually, Castiel changes his mind and desires to make amends in Heaven instead of running. After the situation is resolved, Castiel removes Fred's powers when he wants to make sure it won't happen again. Castiel does the procedure, leaving Fred in a mentally-distant state, but happy. Even though Sam and Dean have come to accept Castiel as a hunter, Castiel nearly tells them he'll return to Heaven until Naomi teleports him and refuses to allow it. Castiel decides to watch out for Fred for a few days, but also to stop running from his problems.
|“|| Castiel: "You don't understand. I have been trying to pretend that I can escape what I did in Heaven, but I can't. All that pain I caused .... I-I have to come back. To make things right.|
Naomi: "And you are ... by doing what you're told. Bottom line: Unless I ring my bell, you stay out of Heaven, Castiel."
— Naomi rejecting Castiel's return to Heaven
in Hunteri Heroici
In Torn and Frayed, he is shown helping people in need, in repentance for his previous actions. He was ordered by Naomi to rescue a fellow angel Samandriel, who was held captive by Crowley in an abandoned building that he locates with Dean's help. Castiel later retrieves Sam against Dean's wishes. During the attack, Castiel gives Sam his Angel Blade to kill demons with and remains outside until Sam and Dean deal with the wards and demons. He was then able to teleport Samandriel to safety, but not before Samandriel revealed to Crowley the existence of an Angel tablet. Samandriel warns Castiel about this and that "they're" controlling him. His mind wiped, Castiel can't remember Naomi, but before he explain Naomi orders Castiel to kill Samandriel, which he does without hesitation. (Throughout the rescue, Castiel saw vague flashbacks of Naomi inserting a certain device into his eye.) He demands answers from Naomi, who reveals that knowledge of the angel tablet could cause great harm in the hands of a demon. Under Naomi's orders, Castiel claims he killed Samandriel in self-defense and that he is taking his body to Heaven to be put to rest (in actuality so Naomi can determine how much he broke), but his weird behavior and the fact that one of his eyes starts bleeding draws their suspicion that something is wrong and that he is being controlled.
In Remember the Titans, Dean desperately prays to Castiel to look after Sam who is not doing so well with his trials. Despite Dean's near-begging, Castiel does not appear or respond.
In Goodbye Stranger, Castiel has become so indoctrinated to Naomi's control that he has no trouble ruthlessly killing a copy of Dean and is shown to have killed hundreds of others. He is sent to locate the Angel Tablet which is in one of Lucifer's Crypts and to stop Crowley from getting it. His interrogation and killing of the demons involved draws Sam and Dean's attention. Castiel claims to Sam and Dean that he is searching for Crowley's half of the demon tablet and that the demons are searching for a parchment that will allow them to translate the tablet without a Prophet. Castiel tortures a demon for information and after learning the location of the being that is telling the demons where to find the crypts, he kills her before she can reveal the truth to Sam and Dean on Naomi's orders. They find out the hostage is Meg. Castiel is able to get Naomi to let Meg explain the truth as she could be useful and afterwards bandages her wounds. Meg flirts with Castiel about their kiss in a few years ago and subtly tells him she wants to have sex with him, something he doesn't catch on to at first. The group travel to the warehouse where the crypt is located and when Dean orders Sam to stay outside, Castiel tells Sam that he is damaged on a level that even Castiel can't heal.
Once inside, Naomi orders Castiel to throw Dean off the trail or kill him, but he is forced to point out the box with the angel tablet in it to Dean as it is angel-proofed. Under Naomi's control, Castiel attacks Dean and tries to kill him, but manages to break free at least somewhat and reveals Naomi's control to Dean. Before he could kills the hunter, Dean tells him that they are family and that he needs him. When Castiel picks up the angel tablet, it severs Naomi's connection with him and all of her control and he heals Dean and explains what happened. However, Castiel senses that for some reason he must keep the tablet safe from Dean as well and disappears with it. Naomi later tells Crowley that Castiel is doing what he is meant to do, which is protect the tablet from all threats. Castiel is later seen riding in a bus with the tablet to an unknown location.
In response to Castiel's departure with the tablet, Naomi starts a search for him, trying to enlist Dean's help in Taxi Driver at which time she claims that he is still insane and was simply misinterpreting her orders when he tried to kill Dean. Despite Castiel's behavior, Dean trusts him over Naomi and refuses to believe her.
In The Great Escapist, Castiel travels between all of the Biggerson's at once, stopping only for very brief periods to throw the angels off of his trail. Its successful until they slaughter everyone in one of the Biggerson's to force him to stop and learn what happened. While he is distracted, Castiel is captured by Naomi, Ion and Esper. Naomi reveals that Castiel has been involved in many atrocities throughout human history, but that his memory of it has been erased because he never follows orders like he is supposed to. Naomi demands the angel tablet, but Crowley arrives, kills Esper, wounds Ion who is revealed to be working with him and drives Naomi off.
|“|| Castiel: How---how many times have you torn into my head and washed it clean?|
Naomi: Frankly, too damn many. You're the famous spanner in the works. Honestly, I think you came off with a crack in your chassis. You have never done what you're told. Not completely. You don't even die right, do you? Where is the angel tablet, Castiel?
Castiel: In the words of a good friend... bite me.
— Naomi and Castiel's confrontation
in The Great Escapist
Kidnapping Castiel, Crowley has realized that Castiel is keeping the tablet close to him in case Naomi ever tries to regain control of him again and shoots Castiel in the gut then painfully pulls the angel tablet out of his body. Before he can do more, he gets a call that Kevin has figured out Crowley's trick and Crowley leaves to deal with the problem, leaving Ion to guard Castiel. Castiel pulls the bullet Crowley shot him with out, overpowers Ion and pushes the bullet through his eye, killing him. Castiel later appears on the road in front of Sam and Dean, severely wounded and weakened and asking for their help.
In Clip Show, Castiel is slowly recovering from his wound. Dean is furious with Castiel and refuses to forgive him for abandoning them again and not trusting him, despite apologies. As Sam and Dean check out how to cure a demon, Castiel goes to get them food. He gets Dean's favorite beer and porn, along with his pie to appease him. Metatron arrives, revealing that Heaven has degenerated into many warring factions. Naomi is only the leader of one, not all of Heaven as he had previously believed. Metatron suggests Castiel do the trials to seal up Heaven so that they can lock the angels together and force them to sort out their problems while keeping the war from spilling over onto Earth. Castiel agrees after Metatron reveals that as the Scribe of God, he knows the trials even without the angel tablet. Castiel is reluctant after discovering the first trial is to kill a Nephilim, the child of an angel and a human. Castiel hesitates as she is an innocent woman, but when she attacks Metatron, he kills her with his Angel Blade.
In Sacrifice, Metatron reveals that they must get Cupid's bow as the next trial and Castiel asks him about God. Metatron describes him as like one would expect: larger than life, gruff, a bit sexist and eminently fair. As they wait for Cupid to come to make the man, Dwight, fall in love, Castiel goes through personal ads to try to make it go faster by finding him a candidate. While they are waiting, Naomi arrives with two other angels and captures Metatron. Castiel faces off against them with his Angel Blade, but lets them go when Metatron tells him to. Needing help, Castiel goes to Dean who agrees after Sam insists. Castiel and Dean bring the angel tablet to Kevin to translate the last trial and Castiel scares him into doing it when he refuses. As they watch, a woman named Gail approaches Dwight and makes him and one of his regulars fall in love. Castiel prepares to confront Gail while armed, but Dean convinces him to talk first. Gail is worried about the state of Heaven and agrees to give them her bow if they really think they can calm it down, but Castiel must cut it out of her hand. Kevin contacts them to let them know that while he has found the trials, he doesn't see anything about killing a Nephilim or the bow of a Cupid. At that moment, Naomi arrives and though Castiel goes to fight her, she insists she just wants to talk and Dean gets him to hear her out. Naomi tells Castiel that she has learned from Metatron's mind that what he is doing isn't going to seal Heaven up, it will instead expel all angels from it permanently. She expresses remorse for her actions, telling Castiel and Dean that angels were meant to protect humanity and lost sight of that somewhere along the way.She also informs Dean that if Sam completes the trials he will die as he makes the "ultimate sacrifice" to seal Hell. Naomi offers to hear Castiel out if he really wants to return to Heaven before disappearing. When Kevin can't confirm what Naomi told them through the angel tablet, Castiel doesn't believe her, but transports Dean to the church where Sam is curing Crowley before departing for Heaven. There he finds Naomi dead with her own torture device impaled in her brain and is captured by Metatron who reveals that she was telling the truth. Metatron takes Castiel's Grace as the last ingredient for the spell he is working and sends him to Earth, but not before telling him that he is now human and Metatron wants him to live a human life, die, come to Heaven, find him and tell him about that life. On Earth, Castiel watches in horror as all the angels begin to fall to Earth as Metatron's spell takes effect.
|“||I guess I trusted the wrong person. [...] I thought I was more important, more effective than I am, and that I could ... fix everything. Now all I can do is keep running. [...] This is all new to me. Hunger. Cold. This feeling ... being all alone.||”|
— Castiel's guilt and struggles as a human
in I'm No Angel
In I Think I'm Gonna Like It Here, Castiel has landed in Colorado and nearly gets run over by a truck. Castiel is left stunned by the cuts on his palms from dodging the truck as he has never experience the types of injuries mortals get before and gets a ride from the driver to a gas station. Reluctantly taking money the driver gives him, Castiel goes to call Dean but meets a Fallen Angel named Hael who is looking for guidance. Castiel suggests Hael take advantage of the new life given to her and go see the Grand Canyon that she claims to have created. Deciding to go with her, Castiel first calls Dean and confirms that Ezekiel is a good guy and can help and then is convinced to come help Dean instead of Hael. She knocks Castiel out and kidnaps him, revealing that she plans to possess him as he is strong and her vessel is weak and deteriorating. In order to stop her, Castiel puts on his seatbelt and then crashes the car, incapacitating Hael while surviving with minor injuries. Castiel takes her Angel Blade and declares his intent to guide all angels in their new lives on Earth, but when Hael threatens to broadcast his location to every angel looking for him if he doesn't say "Yes", Castiel kills her. Later, Castiel starts to dry-clean his bloody clothes at a laundry mat, but needing food and water, steals new clothes and buys candy and a water bottle instead.
In I'm No Angel, Castiel travels towards the bunker, living in homeless camps and trying to avoid angels. After being confronted by and killing an angel one night, Castiel has himself warded against angels being able to locate him with a tattoo. In response, the angel Bartholomew sends rouge Reapers after Castiel. While looking for food in a dumpster, Castiel meets April Kelly, not knowing that she is possessed by a Reaper and goes home with her. April cleans the wound he got from the angel he encountered and they have sex, but while searching for his Angel Blade the next morning, she reveals herself as a Reaper, ties him up and tortures him. Castiel tells her how he didn't know about Metatron's spell and that he doesn't know how to reverse it, but that his Grace was the final ingredient and thus he may be the key to the reversal. When Sam and Dean show up, the Reaper kills him with the Blade. After Dean kills the Reaper, he mourns his friend but Ezekiel takes control of Sam and resurrects Castiel and Dean claims that he made a deal with the Reaper not to kill her if she resurrected him then killed her anyway. Castiel moves to the Bunker with Sam and Dean and is excited by the Bunker's abundance of food and other human necessities and tells a shocked Sam and Dean how he had sex. Castiel sits down to eat, but after learning from Ezekiel that Castiel must leave because the angels are after him, Dean reluctantly tells him so as Ezekiel will be forced to leave Sam and flee otherwise and Sam will die.
|“||There really is a lot to being human, isn't there? [...] There's more to humanity than survival. You look for purpose, and must not be defeated by anger or despair. Or hedonism, for that matter. [...] I do see now how difficult life can be and well how you two have led it. And I think you'll be great teachers.||”|
— Castiel finally understanding humanity
in I'm No Angel
In Heaven Can't Wait, While working as a sales associate at a gas station- and also serving as a baby-sitter for his boss, Nora, although he initially assumed it was a date. Castiel tries to be happy as a human, but struggles to fit in and remains depressed. Castiel calls the Winchesters for help after two people in his area simultaneously combust. With Dean's aid, Castiel determines that the victims were killed by a Rit Zien, a class of angel healers that kill mortally wounded angels. Castiel then goes on what he believes is a date but turns out to be a babysitting gig, growing worried when the baby, Tanya, gets a fever and won't stop crying. Before he can take Tanya to the hospital, the Rit Zien, Ephraim approaches him, having detected his pain. Castiel tries and fails to banish the rogue angel, but before Ephraim can kill him, Dean arrives and tosses him an angel blade, allowing Castiel to kill Ephraim. Castiel then miserly goes back to his normal life at the gas station, beginning to wonder if he should help the angels get back in Heaven.
|“||Nobody told you. Nobody explained. You're just ... shoved out kicking and screaming into this human life without any idea why any of it feels the way it feels, or why this confusion, which feels like it's ... a hair's breadth from terror or pain. Y'know, just when you think you do understand, it'll turn out you're wrong. You didn't understand anything at all. Guess that's just how it when you're new at this.||”|
— Castiel's depression as a human
in Heaven Can't Wait
In Holy Terror, Castiel investigates mysterious angel deaths with Sam and Dean. After "Ezekiel" orders him to send Castiel away, Dean does, explaining partially what happened. Feeling helpless, Castiel decides to pray for aid, when his prayers are answered by Muriel, a neutral angel in the war, who explains that the current conflict is between factions led by the angels Bartholomew and Malachi, but the two are captured by Malachi and his ally Theo. Muriel is killed while Malachi tortures Castiel for information about Metatron, revealing that Ezekiel is dead. When Castiel is left alone with Theo, Theo begs him to help him defect to Metatron who he believes Castiel is still working with. Castiel tricks the misguided angel into releasing him, then slits his throat with an angel blade and steals his Grace, restoring his own powers. Castiel then smites Theo and fights his way out. Disgusted with himself but believing it necessary, Castiel calls Dean to warn him that Ezekiel is dead and thus couldn't have been the angel that helped him save Sam.
|“||If we're going to war, I need to be ready.||”|
— Castiel's resolve to fight as angel
in Holy Terror
In Road Trip Castiel, wearing a new suit and trenchcoat, arrives at the bunker to find the main room trashed and a distraught Dean. Dean explains what happened and how he intends to hunt down and kill the angel possessing Sam for revenge even though it will kill Sam. Castiel however, comes up with the idea of having Crowley do the same thing he did to Samandriel to try to bring out Sam's mind so he can expel the angel. Enlisting Crowley's help, the three take a car that Castiel stole as he can no longer teleport and find the angel. The angel overpowers Dean, but while he's distracted, Castiel knocks him out. After confirming that the angel healed Sam enough that he can finish the job, Castiel watches with Dean as Crowley tortures the angel and follows Dean out when he can't watch anymore. Sympathetic with Dean and forgiving him for kicking him out, Castiel comforts him until Crowley calls them back as he has managed to activate the angel's "factory settings." Castiel is furious when the angel identifies himself as Gadreel, blaming him for everything that has gone wrong in the world. However, Gadreel regains control, telling them that he can withstand the torture for a very long time and they can't stop him without killing Sam. Desperate, Dean asks Castiel to possess Sam to make him aware of the situation, but Castiel is unable to as he would need Sam's permission to do so. When Crowley offers instead in exchange for his freedom, Castiel is reluctant, but removes Sam's anti-possession tattoo so Crowley can possess him. The plan works and Sam expels Gadreel. After Crowley returns to his body, Castiel notes the appearance of Abaddon and the three leave Crowley to deal with her. A safe distance away, Castiel heals Sam's injuries from the torture and some more of the damage the Trials did to him telling him that while he will have to do it in stages and over time, he will be able to finish Sam's healing. Castiel stands a respectful distance away as Sam and Dean speak about Dean's actions and remains with Sam as Dean leaves, alone.In First Born, Castiel is staying with Sam in the bunker and has nearly healed him fully. He is also upset about the fact that he has lost the ability to enjoy human food. However, he discovers that some of Gadreel's grace is still inside Sam and is slowly disappearing every time Castiel heals him. Reading a book and file from the Men of Letters left, Castiel learns that the Men believed that if the grace was extracted, it could be used to track the angel it belonged to. Sam and Castiel begin a procedure to remove the grace, but though it proves dangerous as Sam's body starts to revert to its state before Gadreel possessed him, Sam insists that they continue. With Sam's condition deteriorating as they need more grace then can be safely taken, Castiel chooses to finish healing him rather than take the rest of the grace, destroying the last of the grace inside Sam. Castiel explains that his brief humanity caused him to understand that its not worth it to sacrifice others for the sake of what you need and that he understands where Sam is coming from wanting redemption for his acts as he also wants that, but its not worth his life. Sam and Castiel later use the grace they extracted to try the spell, but it proves not to be enough. Telling Sam that he believes that Metatron is the key to setting things right, Castiel sets out to locate him.
|“||Sam, when I was human, I died. And showed me that life is precious and must be protected at all costs. Even a life ... as pig-headed as a Winchester's. [...] Sam. I want Gadreel to pay as much as you do. But nothing is worth losing you. You know, being human didn't just change my view of food. It changed my view of you. I mean, I can relate now to how you feel.[...] The only person who's screwed up more consistently than you ... is me. And now I know what that guilt feels like. And I know what it ... I know what it means to feel sorry, Sam. I am sorry. [...] You know old me. I would've just keep going. I would've jammed that needle in you deeper until you died because the ends always justified the means. But what I went through ... well, that PB & J taught me that angels can change. So ... who knows? Maybe Winchesters can too.||”|
— Castiel's lesson
in First Born
In Captives, looking for information on Metatron, Castiel tracks down a follower of Rebecca, a friend of Metatron's. The follower reveals however that Rebecca had set up a faction called the Penitents who coexisted peacefully with humanity before all but him were slaughtered by Bartholomew and his followers. Leaving the other angel alone, Castiel is captured by angels working for Bartholomew. To his surprise, despite having his angel blade taken away, Castiel is warmly greeted by Bartholomew who was a subordinate and friend of his in Heaven. Bartholomew invites Castiel to join him in uniting the angels, believing that together they can unite all of the angels under one rule. Bartholomew also has the resources to track Metatron when he appears on Earth and offers Castiel his help with tracking him. However, when Bartholomew captures Rebecca's follower, Castiel is horrified by the angel's torture. When asked to kill the angel, Castiel refuses, saying he would rather die than needlessly kill another angel, wanting peace between the angels, not more war. To Castiel's horror, Bartholomew kills the angel then attacks Castiel himself. Castiel overpowers Bartholomew, but declaring his refusal to kill, Castiel lets him go and starts to leave. When Bartholomew attacks Castiel while his back is turned, Castiel is forced to kill him in self-defense. Visiting Rebecca's grave, Castiel is stunned when some of Bartholomew's followers approach him to lead them in a more peaceful way of existing.
In Meta Fiction, Castiel follows a strange sound to find the Horn of Gabriel and a bunch of dead angels. He finds Hannah alive and heals her, learning that it was Gadreel who killed all of the angels when they refused to join Metatron. Castiel refuses to lead the angels against Metatron and leaves. He is shocked when Gabriel approaches him for help with dealing with Metatron and the two start heading towards the Bunker with Gabriel trying to convince Castiel to help the angels against Metatron, saying that Castiel has been God more than God himself has been. While at a gas station to get more gas for Castiel's car, Castiel and Gabriel are attacked by angels working for Metatron. Gabriel tells Castiel to leave and lead the angels against Metatron while he sacrifices himself to hold the angels off. However, Castiel realizes that it's just an illusion after noticing that a rip in his trenchcoat is no longer there. Castiel proves it by stabbing Gabriel to no effect. Gabriel admits its not real, but that what he said about Castiel needing to lead the angels is true. Castiel comes out of the illusion to find himself tied down in Metatron's office in Heaven. Metatron gives Castiel all of his knowledge about popular culture and explains that he wants Castiel to lead the angels against him as he wants Castiel to be the villain in his "story." In return, he offers Castiel an endless supply of grace to replace his stolen burning out grace. Castiel refuses and before they can discuss it anymore, an angel alerts Metatron that Sam and Dean have captured Gadreel. Metatron trades Castiel for Gadreel, blowing out holy fire and easily overpowering Sam and Dean. Afterwards, Castiel tells Sam and Dean he is on board with stopping Metatron and is angry to find out that Dean has taken on the Mark of Cain. He warns Sam to keep an eye on Dean. The next day, Castiel uses the Horn of Gabriel to call a group of angels to him to become their new leader.
In Bloodlines, Castiel contacts Dean with the information that he has gotten a lead on Metatron causing Sam and Dean to drop the case they are working on and take off to meet him.
In King of the Damned, Sam and Dean meet Castiel at his new headquarters where he is the leader of most of the angels on Earth. He reveals that having killed Bartholomew and with Malachi dead at Gadreel's hands, all the angels have been turning to him for leadership in the war to retake Heaven. Castiel's men have captured an angel named Ezra who works for Metatron and he wants Sam and Dean to interrogate him. Sam and Dean are able to trick Ezra into revealing that Metatron has an elite ground force and that there is a portal to Heaven that Metatron moves around and controls. Before they can learn more, Ezra is murdered and Crowley calls Sam and Dean to offer the location of the First Blade and Abaddon. Before Sam leaves, Castiel asks him his opinion on Gadreel who Sam believes might have been misunderstood before he murdered Kevin. Castiel sets up a meeting with Gadreel, but comes under attack from two angels that he kills. Castiel later meets with Gadreel again, telling him that Metatron has no honor and asking Gadreel to become his spy. Gadreel refuses due to his own honor not letting him abandon the cause he has dedicated himself to, but Castiel tells him to think on it and leaves.
|“||They had no leader, and they insisted on following me. [...] Bartholomew is dead. Malachi was murdered by Gadreel and with Metatron as powerful as he is now, I needed to do something. [...] Dean, this angel-on-angel violence has to end. Someone has to say enough.||”|
— Castiel's as commander of an angel faction
in King of the Damned
In Stairway to Heaven, after an angel named Oran kills himself and an ice cream shop full of people including an angel named Ester, Castiel, Sam and Dean investigate. Castiel is stunned as Oran was one of his men and he killed everyone in Castiel's name. Castiel insists that he didn't order the attack though Dean doesn't believe him. While Dean investigates looking for more angels that might be suicide bombers, Castiel and Sam start chasing down a missing angel named Josiah who they come to believe may be the one who killed Ezra and a traitor. During the trip, Castiel is stunned to learn that Abaddon is dead and is worried about the effect the Mark of Cain is having on Dean. Tracking Josiah to Pray, Montana, Sam and Castiel find a building where the door to Heaven apparently is. Passing tests based on pop culture, they enter a room only to find that its one of Metatron's tricks and that Josiah was caught in a holy fire trap meant for Castiel. Castiel offers to heal Josiah, but he dies rather than owe Castiel his life. Returning to his base, Castiel finds that Dean apparently killed the Reaper Tessa who was working for him with the First Blade though Dean tells him that Tessa killed herself. Before they can talk more, Metatron contacts Castiel's followers, offering them amnesty if they abandon Castiel and insisting that Castiel ordered the bombers, only cares about himself and the Winchester and tells them about Castiel's dying grace. Metatron's transmission makes Castiel's followers doubt him and Hannah demands he kill Dean in punishment for killing Tessa to prove himself. When Castiel refuses, all of his followers abandon him. Castiel returns to the Bunker with Sam and Dean where the three become determined to stop Metatron and are shocked when Gadreel shows up to offer his help, confirming that Metatron was behind the suicide bombers and asking for a second chance. Dean pretends to give it to him then slashes Gadreel across the chest with the First Blade, seriously wounding him and causing Sam and Castiel to restrain Dean.
In Do You Believe In Miracles?, after locking Dean in the Bunker's dungeon, Sam and Castiel go looking for Gadreel who has fled in fear of his life and find him. Despite Gadreel telling Castiel not to heal him due to his weakening grace, Castiel does so anyway and Gadreel reveals that Metatron's plan is to convert humanity into worshiping him instead of God. After Sam and Castiel tell him that Dean used the First Blade to injure him, Gadreel insists that Dean is their best chance to kill Metatron and reveals that the source of his power is the Angel Tablet. Gadreel tells them that if they break Metatron's connection to the tablet, he will be a regular angel again and killable. Castiel decides to sneak into Heaven with Gadreel to find the tablet and has Gadreel pretend that Castiel is his prisoner to get through the portal, getting the idea from Star Wars. In Heaven, Castiel and Gadreel are locked in Heaven's dungeon by Ingrid and Hannah who see through their deception. Castiel tries to convince Hannah to help them stop Metatron, but she refuses to believe him as he promised an end to angel deaths. Gadreel suddenly speaks of his desire to redeem himself, being the only thing he focused on since his first imprisonment in the dungeon for thousands of years and how he lost sight of the angels' true mission; to protect humanity no matter the cost to themselves. Gadreel warns Castiel and Hannah away and then kills himself, using the same sigil the suicide bombers used to create an explosion to free Castiel.
Gadreel's sacrifice convinces Hannah to rejoin Castiel in taking down Metatron. Taking Ingrid captive, Castiel and Hannah try to force her to tell them where to find the tablet, but when she refuses, Castiel orders Hannah to take her out and searches on his own. Eventually Castiel finds the angel tablet in Metatron's typewriter and smashes the tablet, removing Metatron's incredible powers. When Metatron flees an attack from Sam back to Heaven, he finds Castiel sitting in his chair and chains him down. Metatron taunts Castiel with the fact that he has killed Dean, causing Castiel to fail in his attempt to save him by shattering the tablet. Metatron calls all angels "sheep" who will follow him where he wants and shows disgust for humanity. Metatron prepares to kill Castiel, telling him that the angels will never believe him because Castiel can never spin a good story. Castiel agrees, saying that Metatron can however and reveals that he used the equipment in Metatron's office to broadcast the entire conversation over "angel radio." Before a horrified Metatron can react, Metatron's enraged followers storm his office, overpower Metatron and free Castiel. Castiel however locks Metatron in Heaven's dungeon rather than kill him, something Hannah tells him is the act of a true leader. While the angels now once more want to follow Castiel in rebuilding Heaven, Castiel informs Hannah he wishes to be a normal angel again and not a leader. Hannah reminds him that he will die soon when his grace burns out unless he can replenish it, leaving Castiel contemplating the future.
|“|| Hannah: "You did the right thing. Letting him live. It's what a leader would do."|
Castiel: " ... I'm no leader, Hannah. I never was. I just want to be an angel."
— Castiel to Hannah
in Do You Believe In Miracles?
|“|| Hannah: "You're dying, Castiel. You need more grace."|
Castiel: "And we have a mission in front of us that supersedes my needs. All our needs. Don't you agree? You're a good soldier, Hannah. One of the best. And Metatron could not have been brought to heel without your bravery."
Hannah: "Or yours. You must take care of yourself, Castiel."
Castiel: "And another angel should die so I can be saved?! Is this really that hard to understand?"
— Castiel and his fading grace
In Black, Sam finds what he think may be a clue – a man called Drew Neely who had killed his family and disappeared three years earlier has been found dead. Sam theorizes that Neely was possessed by a demon, who may have possessed Dean and left Neely's body to die. Sam calls to share the news with Castiel, who is anxious for news of Dean. Picking up that Castiel is seriously unwell, Sam backtracks and tells him not to worry, that the clue probably isn't anything. Later Hannah visits Castiel. She tells him that rebuilding is proceeding in Heaven; Metatron is in jail, and reconciliation amongst the angels is proceeding. However, some angels remain on Earth, and recently two of them – Daniel and Adina – killed an angel who tried to get them to return to Heaven. Hannah asks for Castiel's help in finding them, and he agrees. Hannah and Castiel travel to find the two rogue angels. Hannah confronts Castiel about his fading grace, but he angrily rebuts the implication that another angel die for him to get more grace. They find Daniel and Adina, who want to stay on Earth, having found much there they enjoy. Hannah persists – that they must return to Heaven; Heaven needs rules to operate. A fight ensures during which Castiel has to kill Daniel to save Hannah. Adina escapes. Hannah continues to insist to Castiel that Heaven needs rules, but Castiel says that the chaos on Earth can produce good things – art, hope, dreams, love – that Hannah points out are "human things."
In Reichenbach, after Hannah heals him, Castiel and Hannah work their way towards North Dakota to meet with Sam who informs Castiel that Dean is now a demon. Castiel's grace continues to fade and he falls asleep at the wheel, causing them to crash. After spending the night at the tow truck driver's house, Castiel awakens to find that Hannah has traveled to Heaven to talk to Metatron about Castiel's grace. Castiel walks in on Metatron claiming that there is some left and he will give it to her in exchange for being released. However, Castiel stops her, accepting his fate. Before he leaves, Metatron claims to Castiel that there really is some of his grace left, but that when he escapes he will destroy everything in his revenge.In Soul Survivor, Castiel and Hannah head towards the bunker to help Sam cure Dean. Along the way, they stop at a gas station where they are ambushed by Adina. In his now severely weakened state, Castiel proves no match who the other angel who beats him badly before leaving him to kill Hannah. Castiel is unexpectedly saved by Crowley who takes Adina's grace and kills her. At Crowley's insistence, Castiel reluctantly takes in Adina's grace and is restored to full health. Crowley asks Castiel to help deal with the Dean situation in return for his help even if it means killing him. Castiel finally arrives at the bunker in time to keep Dean from killing Sam and restrain him. Castiel watches as Sam completes the cure and watches anxiously to see if it works, ready to kill Dean if it doesn't. The cure works and Dean becomes human again to Castiel and Sam's relief. Castiel tells Sam he is temporarily back to full strength again and that while Dean is no longer a demon, the Mark of Cain is still a problem that needs to be solved. He consoles Dean over his actions as a demon and suggests he take time off since things are quiet now.In Girls, Girls, Girls, Castiel and Hannah continue their search for rogue angels to send back to Heaven with Hannah starting to enjoy human things and feelings, displaying an attraction to Castiel that he rebuffs. As they leave the motel they are staying at, Castiel and Hannah are confronted by Joe Johnson, husband of Hannah's vessel Caroline Johnson. Hannah pretends to be having an affair with Castiel to give closure to Joe, but is disturbed by her actions and feelings. Castiel tries to comfort Hannah by telling her of his interactions with his own vessel, Jimmy Novak and how the mission is more important than their vessels or their families. Hannah later reveals to Castiel that she intends to return to Heaven so that Caroline can return to her normal life. After Hannah leaves, Castiel returns Caroline home and inspired by Hannah's actions with her vessel, looks up Jimmy on the Internet to discover that his family is still looking for him. In The Things We Left Behind, Castiel tracks Claire Novak to a group home where he pretends to be Jimmy in order to see her. Claire is upset by his presence as she recognizes him as Castiel, not Jimmy, especially when Castiel tells him that Jimmy is dead and in Heaven. When Castiel asks what he can do to help, Claire asks him to pose as Jimmy and sign her out, but it doesn't work as Jimmy has been gone so long so Castiel breaks her out instead. While Castiel tries to take Claire with him, she runs away and he calls in Sam and Dean to help find her. Sam and Dean tell him stories about their own turbulent history with their father. Dean, knowing he might become a demon again due to the Mark of Cain, asks Castiel to kill him if that happens. Sam and Dean are eventually able to help Castiel track Claire to a man named Randy. They arrive to find Randy tied up by loan sharks and one trying to rape Claire. Castiel rescues her, but while he, Claire and Sam are outside, Dean falls under the Mark's influence once more and slaughters Randy and the loan sharks to everyone else's horror.
In The Hunter Games, Sam and Dean question Castiel about the possibility of a cure for the Mark of Cain, but he informs them it would take a great power to remove it and while the demon tablet might've been able to help them, it's missing. Reluctantly, Castiel suggests calling upon Metatron for help instead and gets Ingrid to bring him to them. Metatron tells them that they need the First Blade for the cure, causing Sam and Dean to call upon Crowley to get the First Blade. At the same time, Castiel visits Claire in a hotel to discover that she is leaving and is trying to cut all ties with him as she blames him and Dean for her father's death. While waiting for Crowley to get back to them, Castiel suggests that Dean talk to Claire and try to convince her of the truth about what happened with Randy. After finding out that Crowley won't give them the First Blade until they have the entire cure, Dean locks himself in the bunker's dungeon with Metatron and tortures him for information when he refuses to tell him the rest without a lot of little favors. Castiel manages to blast the door down in time to stop Dean from killing Metatron and takes him back to Heaven, seeing it as too dangerous to keep him in the bunker with Dean. After returning Metatron, Castiel senses that Claire wants to talk to him and tracks her down. Claire tells him that while she needs to be on her own, she wouldn't be against keeping in touch with him and tells him that he looks better in a tie.
|“||I'm in large part responsible for the way your life has unfolded. I have a responsibility to help you. [...] And you are adrift. I wanna ... I wanna help you have a life.||”|
— Castiel's goal to help Claire
in The Hunter Games
During Halt & Catch Fire, Castiel is searching for Cain in hopes that he would know of a cure for the Mark of Cain. According to Sam, Castiel has had no luck so far but discovered riverboat gambling along the way.
In The Executioner's Song, Castiel continues his search for Cain by interrogating a captured demon. After the demon tells him of a location that Cain has been seen at, Castiel kills him. Searching the location, Castiel finds a massive graveyard and calls Sam and Dean to inform them of it and they tell him how Cain kidnapped serial killer Tommy Tolliver. Cain himself appears, unconcerned about Castiel's angel blade and reveals that he has fallen back under the influence of the Mark of Cain. Believing that his bloodline is tainted, Cain intends to wipe it out despite it being legion. Castiel meets with Sam and Dean at the bunker and after explaining what is going on, Dean decides to kill Cain despite the inherent dangers in him using the First Blade again. After getting Crowley to agree to help them, the group travels to the house of Austin Reynolds, Tommy's 12-year-old son where Castiel is quickly knocked out after his white light proves completely ineffective against Cain. Despite Castiel's failure, Sam and Crowley succeed in using an Illusion Spell to trick Cain into a devil's trap. Afterwards, Dean goes to confront Cain alone, telling the others that they may have to kill him if he returns as a demon and Castiel keeps Sam from following. After Dean kills Cain, he comes out normal and hands Castiel the First Blade instead of Crowley, stunning the demon with his lies. Castiel later tells Sam and Dean that he has hidden the First Blade somewhere, to Dean's relief and Sam privately informs him that Dean is in trouble.
During Inside Man, Sam realizes that Dean is getting worse and calls Castiel to help him find a cure for the Mark immediately. While Castiel is initially reluctant, he eventually agrees and takes Sam to the portal to Heaven to retrieve Metatron once more. However, Hannah, in a male vessel appears to block the way. While she is happy to see Castiel again and that for now at least his grace is alright, Hannah refuses to let them get Metatron, knowing that he will demand his release in exchange for his help which can't happen. Castiel and Sam are forced to leave when Hannah calls in three more angels to keep them from getting into Heaven. Needing another way to get at Metatron, Sam and Castiel use psychic Oliver Price to perform a séance and contact Bobby in Heaven for help in breaking Metatron out. Castiel directs Bobby in how to break out of his Heaven and to open the portal from the Heaven side. After Bobby opens the portal, Castiel enters Heaven where he meets with Bobby who demands to know what is going on. After informing him of the situation, Castiel and Bobby reach the dungeon where they reluctantly release an amused Metatron. Castiel takes Metatron back to Earth where he removes his grace and has Sam shoot him in the leg as a demonstration of his new mortality. Castiel demands the cure or he will have Sam kill Metatron, causing him to admit he'd been lying all along and that he knows of no cure. Metatron tells them that the Mark is God-level or Lucifer-level power and its not even covered on the demon tablet. While Sam doesn't believe Metatron, Castiel is able to tell that he is actually telling the truth and tells Sam to kill him. However, Metatron quickly reveals that there is some of Castiel's grace left and offers to take him to it to get Castiel to spare his life. Castiel reluctantly agrees and leaves with Metatron to find his grace.
In Book of the Damned, Castiel continues his road trip with Metatron to find his grace, getting increasingly annoyed with Metatron's antics as he experiences his new humanity resulting in Castiel punching him in the face at one point. He gets more annoyed as each of the safe houses they check come up empty. As they leave a diner where Metatron has gastrointestinal issues as he is lactose intolerant, they are attacked by an angry Cupid who nearly kills Castiel before Metatron kills him. However, this act doesn't endear him to Castiel who simply continues the trip. Reaching a library, Castiel is able to sense his grace, but its location is hidden from him. Metatron reveals that he doesn't actually know where it is as he had another angel hide it in case of torture but he has clues hidden to find the book it is in. Castiel and Metatron locate the first clue, "what's the maddest thing a man can do" and look for the book titled that. As they search, Metatron questions Castiel about what he will do once he finds the remaining rogue angels and gets them to return home as Heaven is in order now under Hannah's leadership. Castiel doesn't have an answer and is surprised when Metatron stuns him with a spell. Metatron reveals that he is actually there for the demon tablet as well as Castiel's grace and retrieves the tablet while Castiel realizes that they are looking for quotes in books, not titles as he'd thought. Using the knowledge of popular culture that Metatron gave him, Castiel is able to find his grace in a copy of Don Quixiote. Seeing Castiel has already got his grace, Metatron takes the demon tablet and flees. Castiel ingests the remnants of his grace and that combined with Adina's grace restores him to full power and his old status as a Seraph. However, his wings remain broken. Returning to the bunker, Castiel informs Sam and Dean of the return of his full power and lies to Dean about how he got it back, telling him that Hannah got it out of Metatron. Castiel finally meets Charlie Bradbury who is excited by the meeting and jokingly asks him to heal her carpal tunnel. Taking her seriously, Castiel heals the affliction and even Charlie's bullet wound causing her to declare them best friends. Afterwards, Castiel celebrates his return with his friends.
In Angel Heart, after Claire is knocked unconscious, Castiel is called as he is in her emergency contacts on her cell phone. Castiel calls in Sam and Dean to help him deal with her and they discover that she is looking for her missing mother. Feeling responsible as he'd promised Jimmy he'd look after his family, Castiel insists on helping find Amelia before they discover Claire gone. Recalling that Claire mentioned that a man named Ronnie Cartwright was the last to see Amelia, Castiel and Dean go to interrogate him while Sam goes to Claire's motel to cut her off. Castiel gets worried when Dean gets rough with Ronnie, but they learn that he sent Amelia to a faith healer named Peter Holloway. Ronnie tells them that Holloway is the real deal, having healed his blindness, but that he quit after seeing Holloway cut the people sent to him. Dean and Castiel go to Claire's motel where Sam is hacking Amelia's credit card records. After learning of Ronnie's murder, Dean, Castiel and Claire go to investigate it, but not before Castiel tells Sam that Dean is getting worse. At the scene, Castiel determines that the fatal wound was caused by an angel blade but that it seems to be larger and has left three strange markings that he is unable to identify meaning that they are dealing with a fellow angel. After Sam identifies Holloway's location from county records and Amelia's credit card records, he and Castiel go to the farm, leaving Dean behind with Claire due to his worsening condition.
While Sam searches the house, Castiel searches the barn and finds Amelia. He is able to wake her up and she is extremely happy to see him, despite recognizing that Jimmy is no longer in his body. While Castiel is remorseful over his inability to protect her, Amelia assures him that as long as Claire is safe, he kept his promise. Castiel is unable to heal Amelia's injuries, something that disturbs him as that has never happened before. When Dean and Claire arrive to help, Castiel and Dean leave mother and daughter alone. The two find Sam with him and Dean (who discovered earlier) informing each other that Holloway, who's real name is Tamiel is actually a Grigori. Castiel is shocked as he believed the Grigori were supposed to have been wiped out millennia earlier but Sam states that wasn't the case as some survived. When Sam tells him what the Grigori have been doing, Castiel becomes disgusted and angrily questioned where the abomination was. Finding the house empty, Castiel and the Winchesters rush to the barn where they find that Tamiel has killed Amelia. The three quickly engage Tamiel who proves too strong for them, even with Castiel's fully restored strength and he is at Tamiel's mercy. Before Tamiel can kill Castiel, Claire catches him off-guard stabs him through the back with his own angel sword, killing him. The next day, Castiel, Sam and Dean say goodbye to Claire, sending her to Jody until she can get on her feet. Claire has forgiven Castiel for his role in her father's death and keeps a stuffed animal Castiel got her for her birthday and asks Dean to look after him, saying Castiel has been through enough.
During Dark Dynasty, needing Rowena MacLeod to decode the Book of the Damned with Charlie's help and do it in secret, Sam calls upon Castiel to act as her guard. Castiel and Charlie are both unhappy to have to work with Rowena and keep it from Dean, but both ultimately agree for the sake of Dean. Castiel keeps an eye on Rowena and along with Charlie, gets annoyed by her incessant comments. Eventually Charlie asks to leave for a little while, but Sam finds it too dangerous with the Styne Family out there so Castiel locks Rowena in a backroom to give Charlie the privacy she asked for. However, while Castiel is busy doing that, Charlie leaves and Castiel quickly alerts Sam.
In The Prisoner, Castiel is relieved when Sam returns but is upset to learn of Charlie's death. Sam tells him that they are ending the attempts to find a cure and are killing Rowena. Castiel is more than happy to hear that as Rowena has greatly annoyed him. However, Sam receives an email from Charlie post-mortem with information on how to decode the Book of the Damned and decides to continue on. While Sam goes after Crowley as Rowena demands, he sends Castiel after Dean using a low-jack he placed on the Impala. Castiel later arrives at the Styne compound to find everyone brutally massacred by Dean and informs Sam of that along with the fact that Dean is heading back to the bunker. Castiel arrives at the bunker to find that Dean has killed the Stynes there, murdering Cyrus Frankenstein as well despite him being just a boy. Castiel is horrified as in the past, Dean would've let Cyrus go and tries to convince Dean to stop and let them cure the Mark of Cain, saying that while Dean will fight the Mark for as long as he can, one day he will lose control and Castiel will be there to watch him destroy everything. Dean refuses to stop and when Castiel attempts to keep him from leaving, Dean attacks him. Castiel doesn't fight back and is badly beaten. Dean nearly kills Castiel with his own angel blade, but ultimately leaves him alone and warns him that if he and Sam come near him again, he will kill them.
|“||Maybe you could fight the mark for years. Maybe centuries, like Cain did. But you cannot fight it forever. And when you finally turn, and you will turn ... Sam and everyone you know, everyone you love, they could be long dead. Everyone except me. I'm the one that will have to watch you murder the world. So if there's even a small chance that we can save you, I won't let you walk out of this room.||”|
— Castiel to Dean
in The Prisoner
In Brother's Keeper, a healed Castiel talks with Sam about continuing to chase Dean despite the fact that with the Mark, he's unstoppable. Castiel goes with Sam to confront Rowena armed with witch-killing bullets, but she is unthreatened as they need her to decode the Book of the Damned and cast the spell to remove the Mark. She offers a new deal: her freedom and Nadia's Codex in exchange for removing the Mark and Sam agrees despite Castiel's reservations. Reading the Book, Rowena discovers they need a piece of the apple from the Garden of Eden, a piece of the Golden Calf idol, Dean's hair and the blood of the person she loves. When Rowena claims not to love anyone, Castiel reads her mind and discovers she loved a boy named Oskar centuries ago. While Sam goes after Dean following a call from Rudy, Castiel summons Crowley and asks his help in getting the ingredients. Crowley reluctantly agrees and gathers the needed ingredients, including Oskar who Rowena had made immortal. Rowena is furious with them for what they're making her do, but she kills Oskar and casts the spell to remove the Mark of Cain. While she is successful, unknown to the three of them, she also unleashes Amara. To their surprise, Rowena then escapes her chains, immobilizes them and escapes with the Book of the Damned and Nadia's Codex. However, before she goes, she casts the Attack Dog Spell on Castiel, making him draw his angel blade and attack Crowley.
In Out of the Darkness, Into the Fire, Castiel has regained control himself, but is still under the effects of Rowena's spell. Castiel remembers attacking Crowley who is hindered by Rowena's spell on him. Castiel eventually stabs Crowley in the back with his angel blade, but not before Crowley smokes out which Castiel realizes when remembering what happened. Found by a couple of farmers, Castiel flees and is horrified when he talks to Dean on the phone and learns of the release of Amara. Unable to find the portal to Heaven, a desperate Castiel prays for help and Efram and Jonah appear. However, when they chain him up in a warehouse, Castiel realizes that they don't intend to help him, which Efram confirms.
In Form and Void, Castiel is repeatedly tortured for information he doesn't have on Metatron, but the angels don't believe him. Finally, Hannah shows up in her male vessel and puts a stop to the torture, but Castiel tells her to keep him restrained due to the effects of Rowena's spell. At Castiel's request, Hannah tries to heal him and remove the spell, but can't because of the power of it. Castiel explains the release of the Darkness to Hannah to her horror, but when she starts questioning him about the location of the Winchesters, Castiel realizes that its all a trick and Hannah is just trying to get information out of him as well. Hannah reluctantly explains that after Metatron's escape, a lot of angels now hate him again but is interrupted by Efram before she can answer his question of whether she hates him too. Jonah then starts to "hack" Castiel similar to how Crowley and Naomi do it, but while Efram and Jonah are arguing with Hannah, Castiel falls back under the influence of Rowena's spell and breaks free. Castiel quickly overpowers and kills Jonah in self-defense, but Efram kills Hannah for interrupting. Using Hannah's body as a shield, Castiel angrily attacks Efram for his actions and a fight breaks out between them. Eventually, Castiel overpowers and kills him, but is left horrified by the deaths of the three angels, one of which was his friend. He's later found on the ground in the Bunker in pain and asking for Sam and Dean's help.
In The Bad Seed, Castiel is chained to the floor of the Bunker while Sam and Dean try to find a way to help him since he's a danger while under the spell. They realize that rather than killing Castiel as it would a human, the spell has dug deep and is affecting him badly and that Rowena is the only one who can remove it. Castiel is further hurt by hearing "angel radio" from which he learns that the angels are doubling their efforts to find Metatron who the Winchesters know might be their only chance of finding a way to beat the Darkness as the former Scribe of God. However, searches for accidents or moving violations with Castiel's stolen car come up with nothing to Castiel's surprise as he didn't think Metatron would be a good driver. Sam eventually finds a possible clue to Rowena's location and he and Dean take off to check it out, returning with a captured Rowena who they make a deal with: break the spell on Castiel and they will let her go. While they are discussing that and the Book of the Damned with Rowena, Castiel continues the search for Metatron on Dean's computer by trying to search databases for his car using instructions left for him. However, he accidentally activates some porn and stares at it for a moment before closing it down. Castiel falls back under the influence of Rowena's spell, breaks free and stalks a girl through the nearby town. As he's strangling the girl in a warehouse, Dean interrupts and Castiel attacks him too, beating him a bit. Sam finally arrives with Rowena who breaks her spell and then escapes. In the Bunker, Castiel, now back to normal offers to heal Dean, but he refuses, feeling he deserved the beating and forgives Castiel for it. Castiel is upset as they had Rowena captive but she got away because of them saving him, but Sam tells him that they got back Nadia's Codex and Charlie's translations which will slow her down a bit. They'd also have lost the Book of the Damned for good if they'd killed her.
Castiel finds Dean in The Devil is in the Details and tells him to stay far away from the site where the angels attacked Amara. He goes there himself and meets a fellow angel. However, this angel gets consumed by Amara who is proven to be okay. Castiel was shocked to meet his aunt who easily overpowers him but spares him. Amara carves a message onto Castiel's chest and sends him away.
Castiel later follows Dean into Hell to stop Lucifer from hurting Sam. Before Rowena can send Lucifer back into the Cage, Castiel asks the archangel if he can truly beat the Darkness. When Lucifer confirms this, Castiel says "yes" and his vessel is promptly possessed by Lucifer.
In The Vessel, as Lucifer feeds on Sam's soul and prepares to kill him, Castiel fights back and manages to regain control over his body. Castiel tells Sam the truth and that he can't cast Lucifer out as he's using all of his strength just to keep the archangel from killing Sam. He also informs Sam that he can no longer time travel, so they need Lucifer to save Dean. After Lucifer rescues Dean, Dean learns the truth as well before Sam banishes him. The two agree to try to save Castiel from Lucifer, but know that he may not come back willingly since he said "yes" to Lucifer on his own.
In Hell's Angel, Dean and Sam – with the help of Rowena and Crowley – trap Lucifer inside a ring of holy fire and activate an angel suppressing sigil, so they can talk to Castiel and convince him to expel the archangel. Castiel briefly awakens and notices Dean, but before they can talk properly, Lucifer regains control and pushes the angel back down.
Crowley thus decides to enter Castiel's vessel and talk to him directly. Crowley discovers Castiel's safe place to be the bunker's kitchen, where Castiel is watching television. Crowley notices that Castiel has lost interest in the war and doesn't seem to mind Lucifer's presence, saying he mostly just leaves him alone.
Castiel has a jolt of memory that he saw Dean earlier, but gets distracted by the show he's watching. Lucifer arrives shortly after and beats on Crowley. Castiel complains that the two might break something, referring to his television, which he protects. The three of them soon hear Sam chanting an exorcism spell. Once Crowley leaves, it is Lucifer who regains control.
In We Happy Few, Lucifer returns control to Castiel in an attempt to convince the angels to join the attack on the Darkness. The angels aren't inclined to listen to Castiel anymore than they are Lucifer, but Castiel tells them that his role in the battle is to be Lucifer's vessel despite the fact that it is burning him and his vessel out. Castiel insists that he would continue to do it anyway if given another choice and is able to convince the angels to join them.
After the attack on Amara fails, Amara pulls Lucifer from Castiel's vessel, leaving Castiel unconscious on the ground. When Dean wakes him up, he finds that Lucifer is indeed gone, but Castiel is unaware as to where he is. Castiel is helped by the Winchesters and finally meets his creator God who he notices isn't doing to well as he was wounded by Amara.
The team regroup outside to find that the sun is dying. Unsure of how to deal with such a major situation, everyone – including Castiel – start to feel down and hopeless, except for Sam. When they try to get help from the angels and the demons again, Castiel discovers that the angels are planning to lock up Heaven and wait for an honorable death, as they know that God is dying.
Castiel joins Dean on a road trip and explains his reason for allowing Lucifer to possess him. He admits the idea was stupid, but Dean doesn't fully agree. Dean reminds Castiel that he is a brother and best friend to him. Suddenly, the two receive a call from Sam about a plan, which involves creating a soul bomb.
The reaper Billie helps in gathering the souls while Rowena plants it inside Dean, so he can use it to kill Amara. Dean bids everyone a farewell, and hugs Castiel goodbye. Castiel joins God, Sam, Rowena and Crowley at an empty bar. God soon joins Dean and Amara. After a while, the group at the bar discover that the sun has been restored, and deem that Dean's mission was a success.
In Keep Calm and Carry On, after being hit by Lady Toni Bevell's angel banishing sigil, Castiel is blasted through a billboard into a field three hours away from Lebanon. Castiel questions a passing driver on his location then stuns the man in order to steal his truck and return to the Bunker.
At the Bunker, Castiel calls out for Sam only to be confronted at gunpoint by a resurrected Mary Winchester. After a brief standoff, Mary is calmed down by Dean who Castiel is shocked to see alive and hugs. Dean introduces Castiel and Mary who are shocked by who Mary is and the fact that Castiel is an angel respectively. Castiel tells Dean and Mary of the events before he was banished and Dean hacks into the traffic camera footage nearby, using the time Castiel gives him to locate the kidnapper's vehicle.
At the airport, the group locates the vehicle and questions the man who owns it. When he refuses to talk, Castiel attacks him and eventually intimidates the man into giving them the tail number of the plane Toni arrived on. As Dean searches for information on the plane, Castiel listens to Mary about how strange she finds everything including and since her resurrection. Dean returns and tells them that he has learned that the plane has a diplomatic registry, meaning that they can't access its flight plan. Castiel notices a nearby veterinary clinic and realizes that Sam could've been treated for his injuries there. Kidnapping the doctor, the three question him with Castiel getting violent once more when the man refuses to talk. Eventually, the doctor tells them that he was paid $100,000 to treat Sam's leg wound with no questions asked. When it seems he is holding something back, Mary orders Castiel to beat the information out of the man. Finally, the man tells them that he has Toni's phone number as she had called him to ask about the sedative he'd used on Sam. Castiel stands with Mary and watches as Dean calls Toni who refuses to give up Sam.
Driving back to the Bunker, Dean tells Castiel and Mary that they have Toni's phone number and can try to track her phone with it. At that moment, Ms. Watt rams the Impala with an SUV, knocking out Mary. Dean leaves Castiel to watch over Mary while he faces Ms. Watt who arms herself with enchanted brass knuckles that gives her the edge in the fight. Castiel joins in, but the brass knuckles are able to harm even him and he loses his angel blade. Dean and Castiel lose the fight, but before Ms. Watt can kill Dean, Mary kills her from behind with Castiel's angel blade.
Following Ms. Watt's death, Dean and Castiel push her SUV off the road and Dean is able to track the last call on her phone to Aldrich, Missouri. The three depart in the Impala to track down the lead and hopefully Sam.
In Mamma Mia, Castiel, still driving the truck he stole from the man he met after his banishment, searches Aldrich, Missouri for any sign of Sam but is unable to find any signs of him in the abandoned buildings in town. At Dean's suggestion, Castiel begins searching for places rented legitimately given the resources Sam's kidnappers seem to have access to. Castiel is able to locate a farmhouse rented by a woman with a British accent and powerfully warded. Castiel alerts Dean who arrives to check it out with Mary tagging along. Unable to enter due to the warding, Castiel reluctantly stays outside with Mary who eventually enters on her own. After Sam is rescued from Toni, Castiel appears in the farmhouse with Mick who had lowered the wards so that Castiel could enter as a sign of good faith. Mick explains what the British Men of Letters had really wanted and that Toni had gone too far. While the Winchesters are dubious of Mick's intentions, Mick points out that he came in unarmed and lowered the wards for Castiel who could easily kill him. Mick and Toni then depart and the Winchesters return to the bunker with Castiel presumably healing Sam's injuries beforehand.
In The Foundry, Castiel discovers where Lucifer might be, and believing he is responsible for bringing the archangel back into the world, he chooses to hunt for Lucifer alone. Under the alias "Agent Beyonce", Castiel goes to speak with the bandmate of Lucifer's vessel, Tommy, and tells the man to call him if he sees anything. Soon after, Castiel runs into Crowley who asks to join him on the hunt, and Castiel agrees reluctantly, since Crowley knows the location of Wendy Vincente, the sister of Lucifer's vessel.
The two go to visit Wendy and realize she has been healed by Lucifer, who recently paid her a visit. Wendy admits something was off about her brother, and that he had a red-haired company. Castiel is disturbed by the mention of Rowena, though he initially assumes Crowley's true intentions is to save her. Crowley denies it, and tells the angel that Rowena is likely to surrender her services to Lucifer, which will be a major problem.
The two trace Rowena and Lucifer to a cabin in the woods, but once they get there, they find Rowena alone sipping tea, since she had successfully managed to banish Lucifer elsewhere. The three proceed to leave the cabin, with Rowena promising to help them seal Lucifer away should they succeed in cornering him.
In First Blood, he searches for the brothers as he is met by Mary who reprimands him for losing her sons. Eventually, he calls Mick Davies and Arthur Ketch for help before Mary calls him again and he meets with her. She apologizes for her temper as he apologizes since he shouldn't have left and explains he has called for help. They meet the Men of Letters who find the boys' location and they follow them. After locating them, they drive off but meet Billie who reveals the deal with her and the boys. When Mary offers herself in their stead, Castiel snuck behind Billie and stabbed her with an angel blade. He explained to them tells him the world needs every last Winchester, and he won't let any of them die, that they meant too much to him, and he will face the consequences for their deal. His actions left the family in awe at his care for them.
During Lily Sunder Has Some Regrets, Castiel is reunited with his old garrison after he learns that someone is killing angels from the unit. Despite his intent to go alone, he is accompanied by the brothers who want to ensure he doesn't do another reckless act. Later on, he meets with Ishim and Miriam where he is met with distrust because of his past acts but he is allowed to speak with them. They soon fight the angel killer Lily Sunder, the mother of the supposed "Nephilim" who easily kills Miriam and wounds Ishim.
Castiel heals Ishim before he is drained by it and is met by Dean who tells him that May was really human and Ishim lied to him. Shocked, Castiel questions Ishim whose reaction to Dean's accusations confirms it. Ishim attacked them and grabs the weakened Castiel, hissing that he used to envy him for being chosen by God, but now he's sad, pathetic, and weak. Then he proposes to cure Castiel of his human weakness by cutting it out. After Dean tried to counter by drawing an angel-banishing sigil in blood, but Ishim pointed out that this will blast all the angels in the room, and Castiel might not survive in his weakened state. Dean's hand immediately drops.
Castiel watched as Sam brought Lily to fight Ishim before regaining some of his strength. Just as Ishim tried to kill Lily, Castiel snuck up on him and stabbed him from behind.
With Ishim dead, the Winchesters broadly hint that Lily needs to retire her revenge agenda.
Castiel stops them and apologizes to Lily for her daughter and says that he may not have known they were killing an innocent, but ignorance is no excuse and can't imagine her pain. He tells her if she cannot leave and still can't forgive him, he'll be waiting for her revenge. Instead, Lily simply thanks him for killing Ishim and leaves the area.
In Stuck in the Middle (With You), Castiel joins Sam and Dean on a hunt arranged by Mary. The plan is to locate and kill a powerful demon that is loose upon the Earth. When the group - which includes a hunter named Wally - arrive at the demon's house, the five are ambushed by demons. Wally is killed, while Sam and Dean manage to kill two of the demons. The main demon, Ramiel, stabs Castiel with a special lance, leaving Castiel mortally wounded.
Mary knocks the demon out by running into him with her jeep, then takes the group and runs to a barn. Castiel is unable to heal from the injury begins to slowly die. Crowley arrives and tells them the demon's name, while the Winchesters are unfamiliar with it Castiel reveals that the latter is one of Princes of Hell. Castiel reveals they were demonic generals for Lucifer but were believed dead though Crowley states that he had the demons spread the rumor so the princes can live in peace.
When Ramiel reaches their location, he throws Crowley the wall and fights the three Winchesters are able to defeat him by stabbing him with his own lance. The demon's death does not save Castiel, and seeing that he is about to die, Castiel professes his love towards all three of them. He orders the three to leave, but before anyone can move, Crowley wakes up and breaks the lance, having realized that doing so would save Castiel.
Castiel instantly recovers, and the brothers gladly take him back home.
In Somewhere Between Heaven and Hell, Castiel gets a lead on Kelly but he is sidetracked by an angel named Kelvin, who wants to take Castiel back to Heaven to talk with their siblings. Castiel reluctantly goes, being more eager to meet with Heaven's new commander Joshua, than actually going.
In The Future, Castiel returns from Heaven and is met with an angry Dean Winchester. Feeling his absence has betrayed Dean's trust in him, Castiel returns a mixtape Dean had made from him, but is told to take it back since it is a gift. While Dean isn't looking, Castiel snatches The Colt from under Dean's pillow and meets with Kelvin and Hozai outside Dagon's new hideout. While Kelvin compliments Castiel on choosing Heaven over the Winchesters, Castiel corrects Kelvin by telling that he is only doing this so Sam and Dean don't have to spill innocent blood.
The three infiltrate the house. Kelvin and Hozai try and fight off Dagon while Castiel confronts Kelly in the basement. Although his order was to kill Kelly then and there, he sneaks out with her in tow. Castiel drives Kelly to a motel when his truck breaks down. Castiel believes he failed a mission by sparing Kelly, but Kelly insists her son is good. She even encourages Castiel to touch her belly and feel the baby kicking. The sensation puts a smile on Castiel's face.
When Sam and Dean reach their location, the brothers demand to take both Castiel and Kelly back to the bunker and not the Heavenly Portal, through which Kelly and her son will be killed. Although Castiel submits to this decision, Kelly doesn't and drives The Impala to the Portal, taking Castiel with her. Upon arrival, Joshua greets them and asks Kelly to enter the Portal, but any attempt to do so is interrupted by Dagon, who kills Joshua and fights Castiel, as well as Sam and Dean, when the latter arrive.
An injured Castiel stands by Kelly while Sam and Dean get knocked aside. When Dagon returns to finish off Castiel, Kelly takes Castiel's hand causing her son to empower the angel and grant Castiel the strength to defeat Dagon. Castiel tells a surprised Dagon its a miracle before he incinerates her to ash. Sam and Dean are bewildered. Castiel, having been granted a positive vision of the future by the baby, decides to protect the baby in Dagon's stead. He knocks Sam and Dean out and takes Kelly away.
Soon after, Castiel relocates Kelly to a cabin by the lake, and begins purchasing supplies for her in preparation for the baby's birth. Castiel works diligently to the point that he even reads instructions on how to deliver a child. After purchasing a truckload of diapers and delivering it to the cabin, Kelly begins experiencing stomach pains and is forced to stay in bed.
While Kelly is in bed, she asks Castiel about the vision he saw when the Nephilim lent him power. Castiel responds that he saw the future – a paradise without fear or hate that her child will help to create.
Castiel exits the cabin and discovers a rift that leads to another reality. Castiel enters it and finds himself in a war-torn wasteland. He is suddenly attacked by a Tempter Demon, but is rescued by a familiar face. Castiel learns much about this world from the other person before he returns to Kelly in his own world. There, he is confronted by Sam, Dean and Mary.
Castiel gets into a brief argument with Dean who he heals as the latter tells them Lucifer is coming. Castiel tries to stop the brothers but they discover the rift to the alternate reality. Castiel deduces that the portal was created by the Nephilim's powers. The trio enter the portal and arrive in the other world, Castiel tells them of the world's history and tells them a friend there told him. Sam and Dean learn that Castiel's new friend is the other world's Bobby Singer. The trio soon confront Lucifer outside the cabin. Castiel charges forward, intent on keeping Lucifer away from his unborn child, but is easily flung aside. While he lay seemingly unconscious, Sam and Dean work with Crowley in sealing the rift, hoping to imprison Lucifer inside.
Castiel recovers shortly after and enters the rift. Crowley had just committed suicide to complete the spell meant to seal the rift. Ignoring Dean's protests, Castiel charges at Lucifer again and stabs him with an angel blade.
Sam and Dean quickly escape back into their own world, as Castiel returns to their relief only to be met with horror as Lucifer followed him and stabbed Castiel right before their very eyes. The angel collapses dead on the ground, his wings imprinted on the sandy ground. Lucifer is defeated moments after when Mary attacks Lucifer, sending them both tumbling into the rift right before it finally closes.
Sam goes into the cabin to check on Kelly who had gone into labor during the conflict, leaving Dean to stand over Castiel's corpse.
In Lost & Found, Dean briefly stands over Castiel's corpse, grieving, before heading inside the cabin. Castiel's body is later found laid out on the kitchen table and covered with a sheet by two angels. While the male angel - Conrad - believes Castiel deserved what he got, the female angel - Lily - thinks he deserved better.
After praying to God to bring back everyone they have lost fails, Dean and Sam decide to hold a Hunter's Funeral for Castiel. Alongside Jack, who sees Castiel as his father instead of Lucifer, the Winchesters burn Castiel and Kelly Kline's bodies outside the cabin.
In Patience, Dean argues with Sam about how trusting Jack cost Castiel his life. Overhearing their argument, Jack's eyes glow as he calls out to Castiel. In a black realm, the essence of Castiel is sleeping before he awakens, after hearing Jack's voice calling his name. Castiel is left confused at where he is.
In The Big Empty, he wanders through the realm of nothing asking for someone to appear but gets no answer as he is followed by a mysterious being. Castiel soon senses the being's presence and calls out to it, the being is the The Shadow who takes on his form to communicate and so he wouldn't be afraid of its true form. Castiel then learned the details of the realm which is called The Empty, which is where angels and demons are sent after death before being put in eternal slumber. The entity remarks that Castiel was awake as it states that nothing ever awakes there but Castiel is awake for a reason and has awoken the entity because of it. The entity questions Castiel who didn't know suggesting the Winchesters had a role in it but the entity rebuffs this, as it only had power in the realm and decides to probe through his memories in an attempt to find out what could've woken up Castiel as he is put in intense pain.
Afterwards, the shadow explained to Castiel, who remains in pain, what he did and that he wants Castiel to go back to sleep. Castiel realizes from the entity's description that having Castiel awake is painful for him which the entity confirms, stating that if Castiel can't sleep, it can't sleep. The entity insists that it likes and needs sleep, causing Castiel to suggest that it get rid of him by sending Castiel back to Earth. The entity suggests that it instead throw Castiel so deep into the Empty that he can't bother it anymore, but Castiel recognizes that the entity is bluffing and that it won't work as the entity would've already done it if it would work.
The entity acknowledges that Castiel is right, but refuses to send him back, telling Castiel that "its not part of the deal" and how he doesn't want to return. Castiel stated his friends needed him but The entity states that it has gone through all of Castiel's mind and knows everything there is to know about him and claims that there is nothing back on Earth for Castiel. The entity grasps Castiel's head and painfully shows Castiel visions of his grace being stolen by Metatron, his death at the hands of Lucifer, the Escape of the Leviathans and Castiel returning the souls to Purgatory. The entity then beats Castiel, attempting to convince Castiel he's worthless so he would return to sleep. However, Castiel refuses the entity's demands and declares that since he is awake that no matter what the entity does, he will keep it awake and fight it for eternity if he is not released. The Shadow angrily denies Castiel's words as Castiel boldly continues to demand his release from the realm and stares down the entity.
Castiel later awoke in a meadow on Earth and realized that The Shadow, has complied and resurrected him, just as he demanded. Castiel then basks in the sunlight, happy to have been brought back to life.
In Advanced Thanatology, Castiel traveled to a small town where he uses a pay phone to contact Dean who is shocked to hear him. The Winchesters travel to the area and are surprised to see Castiel alive again as he greets them with a nod.
In Tombstone, Dean and Sam are still shocked at seeing Castiel alive again as he confirms its really him and explains he annoyed an ancient cosmic being so much that it sent him back. With that, he is embraced by the brothers who questioned if he was in Heaven but Castiel replies that he was in The Empty and tells the surprised brothers that his experience there was horrible as it was like travelling through an endless void of nothing. He explains he was awoke from his slumber after hearing a voice say his name, as he states his belief that the brothers had something to do with but they reply it wasn't them as they believed it was impossible. He is then is asked if God had something to do with it but Castiel replies God doesn't have control there as the brothers soon realized that Jack had a role in it and go off to tell him about it. Castiel returns to the Bunker with them and finally meets Jack who is shocked to see him alive and Castiel thanks him for his part in bringing him back. In response, Jack hugs Castiel, extremely happy to finally meet him and shows what he has learned from his time with the Winchesters.
While working on an assignment, Jack and Castiel catch up with Castiel apologizing for not being there when he needed him but the latter assured him it was alright as he understood it wasn't by choice. When Jack gets a lead, he goes to tell Dean though Castiel warns him but Jack learns the hard way as Dean points a gun at him. The group split up with Castiel going with Dean while Sam goes with Jack for other evidence, Dean makes Castiel wear a cowboy hat as they get information about the monster from the police.
They meet up with Jack and Sam who met the mortician Athena Lopez but they don't believe her to be a potential monster as it makes little sense. The group then learn of the truck found at the murder being stolen and review the footage of it before the murder. Dean recognizes the driver as an outlaw from the 1800s. They realize that Jack was right about it being a hunter's case but the monster was a Ghoul, which Castiel explain to Jack who soon recognizes him and reveals the ghoul as the mortician's boyfriend.
After tracking the Ghoul to a bank, a gunfight breaks out. In an attempt to stop it, Jack ignores Castiel's pleas and unleashes a telekinetic blast that throws the Ghoul and a security guard back. The security guard hits his head on a pole and dies with Castiel being unable to heal him as Jack breaks down. As Jack seems to be struggling with the fact he has killed someone, Dean has Castiel and Sam take him back to the bunker as he deals with the ghoul. Once there, Sam and Castiel attempt to console him and tell him that he just made a mistake Jack seems to be taking it harder than the others realize. When Dean returns, he explains he had the ghoul take the fall of the guard's death as Jack has an outburst regarding the dead man and is scared that he will hurt the others saying the they are all he has and he can't hurt them. Jack throws them back saying he is sorry and teleports out of the bunker.
In War of the Worlds, Castiel searches for Jack and makes contact with angels for help and tells the brothers he'll handle it alone. Going to a park, Castiel meets with the angels who want him to help find Jack and use his power in order to rebuild their race which was depleting after Metatron's actions. Things turn hostile, as Castiel engages them in battle and is nearly taken down but the three angels are stopped by Lucifer's return to the main reality as he orders them to release Castiel, threatening them as he does. The three angels release Castiel and flee as Lucifer collapses on a bench out of energy in his weakened state.
Castiel was shocked and angered to see his brother again, nearly killing him for revenge for his previous deaths but Lucifer warned him of the potential danger of it as they talk for a while explaining how they are both back after their previous encounter before Lucifer tells him of an impending threat.
Following this, Castiel and Lucifer go to a bar where Castiel reluctantly sits with Lucifer to talk about Jack despite their differences, apologizing sarcastically for stabbing Lucifer the last time they met. Castiel briefly talks with Dean before his phone is taken by Lucifer who doesn't want the Winchesters involved. They can continue talking with Castiel appearing to be willing to put aside his differences with Lucifer for Jack's sake and due to the threat of the alternate Michael however, Asmodeus arrives and captures them after subduing them. With him imprisoned, Asmodeus steals Castiel's phone pretending to be him after Dean calls and he tells he is alright. Asmodeus places Castiel in a cell to use as a bargaining chip while Lucifer is put in an adjacent cell for potential in the conflict with the invading Michael.
In The Bad Place, Castiel is mentioned by Jack to being one of the few people besides the Winchesters that Jack sees as his true family.
During Various & Sundry Villains, Castiel remained in his cell trapped with Lucifer and was promised torture by a guard demon. As he bemoaned his time, he talked with Lucifer who asked for some of his grace to break out but he refused and doubted his claims about Michael. However, Lucifer states he wouldn't lie about that comparing the other Michael to their own Michael in which they will stop at nothing after setting their minds to something. Castiel then asks how much time they had with Lucifer mentioning very little while even bringing up the torture the latter administered on Mary Winchester. Castiel was horrified to hear this as Lucifer taunted him but he retaliated by describing Jack's ways which were opposition to his father who he detests. His taunts cause a furious Lucifer to bring out some of his powers. Lucifer soon frees Castiel and they keep up the act of insulting each other as the same guard demon Dipper returns. When the latter agrees with one of Castiel's taunts, Lucifer overpowers him and manages to wound him as Castiel smites him. The two proceed to leave their cells before they are confronted by more guard demons but they manage to kill them and escape the area. Outside, Lucifer rests as Castiel warns him of the threat and Lucifer hints that he would be more of a help if Castiel would lend him some of his grace but the latter refuses even stating he won't make the same mistake. Lucifer gets angry and attacked him to take some of his grace but in his weak state, Castiel is able to stab him as he states he is making up for his previous mistake.
In Devil's Bargain, Lucifer escaped Castiel and the latter searched for him before collapsing in the woods. He was found by a small boy who mistook him for a corpse who he showed to a friend before they poked him and he woke up scaring off the boys as he wondered of his surroundings. Castiel returned to the bunker and spoke with Sam and Dean who he tells of his imprisonment by Asmodeus for weeks. He reveals it was Asmodeus mimicking him and using his phone to monitor them. When asked why he was captured, Castiel states it was because of the latter wanting Lucifer who he reveals to the surprised brothers has returned from the alternate reality.
The brothers ask how he could have came back, as Castiel reveals it was due to the other world's Kevin Tran using a spell to allow it. Castiel confirms they have an angel tablet which that world's Michael intends to use so he could invade their world, a statement that leaves the brothers shocked. He confirms his beliefs by mentioning Lucifer was afraid of Michael and wanted to help though brings up the latter's attempt to kill him after they escaped.
The brothers move to make a plan before asking about Mary and Castiel reveals she's alive but knows very little of her wellbeing. They bring in Donatello Redfield and plan to have him read a spell on an angel tablet that could open a rift to the other world so they could locate their mother and Jack before Michael harms them. They decide to search for and capture Lucifer who is in a weakened state.
Castiel and the Winchesters traveled to Missouri, where they meet a beggar who met Lucifer and he tells them where he went. At night, the Winchesters and Castiel go to Sister Jo's building but find Arthur Ketch instead and he says he was tracking Lucifer but proposes a team-up. Distrustful, Castiel knocks him out and they stuff him in the impala's trunk to question him and kill him.
The Winchesters soon track Jo's card to the motel and meet her where Castiel reveals she is an angel and she leads them to Lucifer. A confrontation breaks out, as Dean tries to capture him but Anael helps the archangel who overpowers them and proceeds to torture them but Arthur Ketch arrives and throws a demon bomb but Lucifer whisks himself and Anael away.
The group question Ketch on his help as he explains he has to draw the line somewhere and again offer to help them. He reveals he is working for Asmodeus and can as a double agent for the Winchesters since he knew of Lucifer and the invading Michael's threat.
At the bunker, Castiel asks if they can really trust Ketch but the Winchesters assure him that they would kill the man should try anything.
During Good Intentions, Castiel apologizes in advance as he painfully strips the spell from Donatello's mind. Afterwards he leaves the room, he tells the brothers he did what needed to be done as they tend to the prophet. When the brothers return from the hospital, they angrily tell Castiel Donatello is alive but brain dead and hooked to machines now. Castiel justifies his drastic action by revealing Donatello was working for Asmodeus though unwillingly. He tells them what they need to open the rift to the other world.
In A Most Holy Man, Castiel is mentioned to have gone to Syria to procure the Fruit from the Tree of Life.
In Scoobynatural, he returns to the bunker where he searches for his friends to tell them of his success but mentions he thinks he may have married a Djinn queen after bartering with her and killing some followers. Castiel finds no sign of the brothers but hears a television and sees to his disbelief that they were sucked inside. At a loss of words, Castiel sees purple lightning before he is sucked into the TV as well.
Castiel finds the brothers as they traveled with the Scooby gang and follows them. He then meets the Scooby gang and is confused by how their dog can talk which he points out to the brothers. The group splits up to investigate with Shaggy and Scooby, to his annoyance. After they find the ghost, Castiel notices something off before running with his group.
They all meet up, and the Phantom attacks them, with Fred getting injured, and Shaggy getting thrown out through the balcony door. Sam and Dean drive off the Phantom, using iron candlesticks and find Shaggy holding on for his life. Scooby jumps to save Shaggy and Castiel jumps and slows their descent to the ground, but Shaggy's arm gets broken. With Shaggy's injury and the unexplainable abilities displayed by the Phantom, the Scooby Gang is confused by the unusual circumstances. Castiel, Dean, and Sam decide to tell them that all the paranormal stuff is real, including the ghost. Castiel is shocked as the Scooby Gang begins to have a nervous break down by this revelation, but Dean stops them by mentioning their past acts to encourage them, which gets Sam to reveal he watched the show as well.
Before they leave, the three find the Scooby Gang suffering a second nervous break down which Dean states they can't leave them in. To set their minds at ease, they have the ghost disguise itself as Cosgood Creeps in the Phantom costume, making the cartoon heroes believe the whole thing was just another staged set up by a normal human. Castiel secretly healed Shaggy's broken arm, making the latter think it wasn't injured at all. Castiel then hugs Scooby and Shaggy, praising their brave acts in saving each others life. Castiel also jokingly mention about "Danger", which promptly make Shaggy and Scooby running.
The child returns Castiel and the Winchesters to the real world, and they destroy the knife in the television, putting the kid to rest. Afterwards, they go back to the pawn shop, finding Alan about to sign his store over to Jay, and confront the Real Estate Developer of his crimes, knowing he used the ghost to drive off owners to buy their property and then on Sam and Dean when they got to close to discover his plan. While they knew he would never be arrested for those actions, they hacked his finances and had him arrested for tax evasion.
As Jay is arrested, he uses the meddling kids quote from Scooby Doo and Dean uses Scooby's phrase but Sam and Cass tell him to cut it out.
During Bring 'em Back Alive, Castiel returns to the bunker and is shocked Dean went to Apocalypse World alone and is not all moved to hear Arthur Ketch is with him. Castiel then sees his brother Gabriel and remarks to Sam that he didn't tell him that he was in a worse state than he described. Castiel tends to him but Gabriel's condition remains the same as they tend to him but wonder if he'll truly be alright after he refuses his own grace. They also wonder how he is still alive before Castiel suggest he might be too gone.
The two leave and Castiel returns to see Enochian Language on the wall, he alerts Sam of this. Castiel translates the writing and it tells him and Sam how Gabriel faked his death by creating a duplicate which Lucifer stabbed into. Gabriel then went into hiding and lived a life freed of being tethered to Heaven and humans before he was kidnapped by Asmodeus who would steal his grace to grow stronger. From this, they see Gabriel's mind is still intact but he may not trust them to fully communicate. Castiel tries to fix his thoughts states he is unable to actually heal Gabriel and believes they just have to wait on him.
Eventually, Gabriel speaks to Sam as he slowly regains his powers. Castiel and Sam are relieved that he is back to normal and give him some of his grace. However, Asmodeus (who detected Gabriel's power) calls Sam and tells him to hand over Gabriel or he'll come to them and destroy the bunker.
Knowing the severity of the threat, Castiel and Sam try to ward off the bunker from the Prince of Hell but it was for nothing as Asmodeus and his forces invade. Castiel kills several demons including one that tried to kill Sam before they were knocked away by Asmodeus who states the warding couldn't stop him. As demons take Gabriel away, Asmodeus begins to inflict pain on Castiel and Sam. Seeing this, Gabriel breaks free of his captors and heals himself, he kills Asmodeus by incinerating the demon, saving his friends.
Afterwards, Castiel and Sam caught Gabriel up on everything that has transpired by, such as an alternate universe Michael trying to invade their world, Jack being sent to the Apocalypse World and they asked him to help them but he declines and tells them that he will put his faith in them. Castiel begs his brother to not walk out on their father's work but he again declines, as he wanted no part in the conflict and he left the bunker.
When Dean returns, he is informed of the events that occurred but was angry at the latter's refusal to help. Castiel swore to Dean that they'd find Gabriel again.
In Funeralia, Castiel and the Winchesters try to track down Gabriel but have no luck. They contact Rowena who ignores their pleas and Sam complains about this before going over his computer. Castiel decides to go to Heaven for help before he reveals news about killing people who had heinous pasts.
Castiel arrives at the Heavenly Portal, finding it unguarded before he finds the guard Indra trying to get drunk. The guard tells Castiel cryptic description about Heaven's state and lets him pass. Castiel goes to Heaven where he meets Duma and two other angel, he tells them he needs the angels' help in finding the archangel Gabriel who he reveals is still alive. He also explains that he needs them in fighting an Alternate Michael who wants to invade and conquer their world. Though wary, Duma hears Castiel out and decides that maybe they can help each other after all and leaves Castiel sitting in Heaven's Throne Room for a long time. Finally, Duma returns, asking about Gabriel and getting him to Heaven. When Castiel admits that he doesn't know where Gabriel is and asks Duma to send a few angels to search for him, Naomi arrives and explains that Duma can't. Seeing Naomi, Castiel becomes surprised and angry before he questions her survival as she reveals that the drill couldn't kill her. She takes Castiel to her old office to speak with him, leaving Duma and the other angels behind.
In her office, Castiel admits that he was relieved when he'd believed Naomi to be dead, causing Naomi to comment that they never did see eye to eye. Castiel angrily confronts Naomi over her actions such as stealing his memories, threatening to tear him apart, making him repeatedly act out Dean's murder and killing many, many people in front of him. Naomi simply states that "those were simpler times" and explains that after Metatron attacked, she had a few reliable angels spread the word that she was dead.
Castiel notices Heaven's power flickers, as Naomi asks him if he knows what powers Heaven. After he tells her that its angels, Naomi explains that every angel is like "a walking, talking battery." Gesturing to the power flickers, Naomi explains that its what happens when they run out of power. Castiel is then told that there are a grand total of nine angels in Heaven, including the two of them and one or two on Earth "and that's all. We are the last men and women and divine waves of light standing, as it were." Castiel is horrified by the news, having known that their numbers were small, but not that small.
Naomi tells Castiel that they can't help him because no angel can leave Heaven, they are the only thing still keeping the lights on "barely." They need more, especially an archangel. Naomi states that the others thought that any archangel would do and dismisses it as "a long story," but Castiel's news about Gabriel is blessed as with his power, the angels can keep Heaven running. Without Gabriel, the angels will burn out in time, Heaven will crumble and all of the souls in Heaven will fall back to Earth. This would mean billions upon billions of ghosts unleashed upon the world with massive chaos and death.
Castiel returns to Earth, as Naomi accompanies him through the Heavenly Portal. Naomi asks that if Castiel finds Gabriel to let him know about what is happening in Heaven. Naomi promises that if Castiel can't, the angels will do their duty and keep things running for as long as they can. Though Castiel promises that they will find a way to fix the problem, Naomi appears resigned to their fate, suggesting that what is happening is one of the things that simply can't be fixed and "everything ends." Naomi tells Castiel that until the situation is resolved, the Gates of Heaven are closed. After sharing a nod with his sister, Castiel watches Naomi depart through the portal which seals behind her.
During Unfinished Business, Castiel is mentioned by Dean to be searching for Gabriel in Texas. He is later mentioned to be helping Gabriel (who decided to join) in settling in the bunker.
In Beat the Devil, Castiel and the others prepare the spell for the ritual as he tells everyone Gabriel is extracting his grace in Dean's room. However, it wasn't enough grace to open the rift and this caused the others to reconvene about the plan. Castiel suggested tracking down Lucifer as he is the only choice, Dean and Sam were against this since they had too much experience with him. Castiel convinces them they have no choice since Lucifer was always their responsibility since he was let out of the cage.
Agreeing Sam tells Castiel and Dean he has plan, they go to notify Rowena and Gabriel who just finish having sex of Sam's plan.
After Rowena and Gabriel capture Lucifer, Castiel personally cuts his brother's throat for his grace to power the rift. Once the rift opens, Castiel and the others leave Lucifer with Rowena as they head to the other universe.
In Apocalypse World, Castiel talked to Gabriel and told him of Heaven's state and how it may need him to maintain its state. Gabriel is reluctant since he once abandoned it as Castiel reassures him. The group come across humans who they save from a vampire, Castiel learns that since the angels have exterminated most of humanity, the monsters are getting hungry and wilder for humans to devour. They are then told that Jack and Mary are at a camp which is where they are headed and there is a shortcut but vampires are there, Gabriel wanted to avoid it but Sam and Castiel tells him it is the best way.
Traveling through a tunnel, they deal with swarms of vampires which they fight off. Unfortunately, Sam was attacked by vampires and was dragged off by the vampires screaming. Castiel went after him and killed the vampires but was horrified to find Sam dead and told Dean not to look to look at the carnage.
Very soon, they find an area with warding that weakens Castiel before Gabriel cancels it out and they find Mary who Castiel is happy to see as she is surprised to see him. Mary takes them to the camp and Castiel reunites with Jack. When Jack becomes distraught at Sam's fate, Castiel tries to comfort him but the latter turns him away and asks why they didn't revive him. Both Castiel and Gabriel tell their nephew that they aren't strong enough to resurrect Sam. However, a surprising sight arrives it is Sam alive but with Lucifer whose presence shocks Castiel.
During Exodus, Castiel is shocked to see Lucifer and pays witnesses to the tense moment between him and Dean which ends with Jack teleporting away. Lucifer volunteers to help them against Michael as they can't do so alone. Castiel then submits Lucifer to Supernatural Handcuffs if he is really willing to help and escorts his brother after Lucifer is punched by Mary. When Jack returns, Castiel becomes worried after the latter decides to talk with him and tries to discourage him but to no avail. Later on, Castiel tries again though he is forced to agree that Lucifer has point in not being able to spread evil while trapped in Lucifer's Cage.
Castiel travels with the group, he is uneased with Lucifer with Jack and tells Sam that Gabriel went ahead. Gabriel appeared while being chased by a squad of angels, Castiel prepared for a fight but Lucifer easily killed them, revealing the cuffs had no effect.
Afterwards, Castiel takes part in the interrogation of a Resistance Traitor and at Dean's signal tortures him until the latter reveals he allowed the Alternate Charlie and Arthur Ketch to be captured.
During the attack on the angel camp, Castiel intercepts his fleeing counterpart and quickly overpowers him after pinning him to the vehicle with an angel blade to his throat. Castiel is not too shocked to see him as his fascinated counterpart is to see there was "more than one of us." Castiel is disgusted that his counterpart would align himself with Michael and hurt humans and tells him that he much prefers humans to angels. His double states that he isn't any better than him and they are the same. Agreeing with the sentiment, Castiel stabs his other self in the abdomen with his angel blade, killing him.
Castiel takes part in the evacuation to the prime world, after he emerges through the rift he greets Rowena who remarks it was about time before Sam and Dean arrive as well after leaving Lucifer trapped.
During the celebration, Castiel was sad to hear that Gabriel was killed by Michael but was pleased his efforts weren't in vain. He asked about Lucifer and was told by Dean that Sam handled him.
In Let the Good Times Roll, Castiel goes on several hunting cases with the Winchesters and Jack before they receive shocking news. One of the humans Maggie was killed by an unknown assailant and Jack goes off to hunt down the possible killer.
Following Jack to a gas station, they stop him from hurting an innocent employee and he leaves shocked that he hurt someone again. As they worry, angel talk is heard and they see a figure watching them before rushing out after the windows are destroyed and the cause is revealed to be Michael who greets them. Shocked to finally meet the Alternate Michael, Castiel becomes angry after remembering Gabriel's death and quickly tries to attack in anger, despite knowing the power Michael wields but is stopped by Sam from fighting while Michael provokes him. Dean then ignites holy fire to keep the Archangel at bay as they retreat from the area.
They returned to the bunker and wondered how Michael made it to their world before they see Maggie alive as she was resurrected by Lucifer who also returned but took Jack.
The group started to plan before Michael arrived and Castiel engaged him but Michael effortlessly knocked out Castiel. Sam prayed to Jack for help and the latter arrived and severely wounded Michael. Castiel woke up and joined Dean and Sam in telling Jack that Lucifer allied with Michael to enter their world and criticized his brother for leaving them to be killed while he makes off with Jack.
Unlike Dean, Castiel was unwilling to let him possess Dean as he, somewhat correctly, believes that Michael would take full control over Dean. He watches as Dean states he has no choice since his family is in danger.
Afterwards, Mary and Bobby return to the bunker where they find Castiel sitting down, bemoaning Dean's fate as the vessel for the corrupt Archangel. As Mary and Bobby approach him, Castiel simply shakes his head in despair, as he knows what had happened.
In Stranger in a Strange Land, Castiel contacts the demon Kipling in an attempt to locate Dean. Meeting at Martha's Mowtown Meats, Castiel questioned Kipling who expressed surprise that Castiel wanted to meet with him and that Castiel was looking for Dean when Kipling believed them to be "joined at the everything." Kipling questioned Castiel on what would be in it for him if he answered Castiel's question and Castiel told him that Kipling would get to live if he did and if he didn't Castiel would burn him to ash. However, Kipling revealed he had anticipated this and had the other demons in the restaurant (who were patrons and staff) reveal themselves and they beat Castiel to a pulp. Restrained, Castiel watched as the demon called Sam using his phone to demand that Sam meet with him if Sam wished to see Castiel again alive. As they waited for Sam to arrive, Kipling offered Castiel a drink despite acknowledging that it had no effect on either of them due to their respective natures. Castiel watched as Kipling negotiated with Sam over being the Ruler of Hell before a fight broke out and ended with Sam killing Kipling and abolishing the title. Castiel was soon released and went home with everyone.
Later on, he apologizes to Sam for letting himself be captured but Sam relieves him of guilt as he may have did the same. Castiel soon goes into Jack's room while Jack is wallowing in self-pity of his own powerlessness and uselessness. Castiel reassures Jack that his grace would regenerate in time and that even if Jack doesn't have his powers, he still has his family, although it does not work as Jack is still frustrated by how without his powers, he cannot stop Michael.
In Gods and Monsters, when Jack goes over lore about his grace returning Castiel tells him it might take longer because of his human status being a factor. Jack is angry since Michael could cause serious damage in that time and he can't stop it.
While at the bunker, Castiel speaks to Nick who notices his nervousness around him. Even though Nick assures Castiel, he is still put off when remembering his brother. After Nick regains part of his memory and breaks down at Lucifer taking advantage of him, Castiel (recalling his own possession by Lucifer) relates to him and tells the man that is what Lucifer did to everyone. Soon, Castiel notices that Nick is still suffering from Lucifer's influence after he snaps his fingers at Castiel in a Lucifer-like manner after being enraged. Castiel examines Nick and determines that while Lucifer is gone, he may have done more damage to Nick's psyche than they realized. Castiel admits to sympathizing with Nick, explaining his own history with his vessel Jimmy Novak. However, Nick sees Castiel as no better than Lucifer for what he did to Jimmy, leading Castiel to tell Nick that what happened to Jimmy and his family is the biggest regret of his long life.
After Jack returns to the bunker, Castiel is irate at his reckless action though stops after Jack states he needed clarity. Jack soon asks about a way to stop Michael, Castiel tries to consider one while Jack states they might have to kill him, something that causes Castiel to argue with his statement as Dean would die too. However, Jack states Dean would rather die than suffer at the Archangel's hands.
During The Scar, Castiel and Jack are reunited with Dean who they are happy to see but question on what became of Michael and the latter's intentions. Dean responded he had no idea and went to rest, as Castiel confirmed to Jack it is Dean. Much later, Dean finds himself with a scar on his arm and has no memory of it along with his possession by Michael, Castiel accesses his memories to find out why Michael left Dean and what left a strange scar on Dean's left arm. This triggers a memory of Michael being stabbed in the arm by the hooded figure with their spear, Castiel questioned who the figure was. Castiel and The Winchesters contact Jody Mills who has been investigating three murders she thought were done by a human serial killer but realizes were done by the mysterious person when they describe the weapon. Castiel tries to go with the brothers but a girl who was cursed by a witch comes in and he has to tend to her.
Very soon, the girl who was cursed has succumbed and Castiel has to tell Jack of it. He watches Jack mourn her before he gets an idea, he examines the witches' corpse and deduces her spell is still in effect and spots the necklace she was wearing. He destroys it and the essence goes back to the girl who is resurrected and returned to normal. Castiel congratulates Jack and promises to put in a good word to Sam and Dean about going on a case, to Jack's joy. Castiel noticed Jack was seemingly sick and was told, he was having his first cold and he left thinking everything was alright.
During Unhuman Nature, Castiel tends to Jack and finds something is wrong with his body and after he collapses they take him to a hospital. Castiel learn Jack's body is shutting down as he becomes worried. The group contact Rowena and she agrees to help after Jack thanks for saving him. Once Rowena diagnoses Jack, they learn that grace needs to reconstruct his body cells and Castiel's won't do after he offers, as Rowena states only that of an Archangel will do. They contact Arthur Ketch who directs him to a Shaman the men of letters went to. The man was known by Sergei who Castiel decides to meet alone. As Castiel approached Sergei, the latter trapped him in holy fire. After learning that Castiel was alone, he released him. Sergei assured Castiel that his job is solving the unsolvable and gave him a spell and a vial of Archangel grace, which Castiel learns came from Gabriel who went to Sergei before hiding. Castiel asked what he wanted as the man requested for him to tell Sam and Dean that they owe him one.
Castiel returned with Sergei's spell and the grace as Rowena did the spell. It initially seemed to work but it is revealed to have only made Jack's condition even worse, Castiel called Sergei for help. The Shaman told Castiel it was just an experiment and Castiel threatened Sergei, that if Jack dies, he would find him. An unfazed Sergei responded with "you can try".
In Byzantium, the group watch over a dying Jack and Castiel goes to talk with Dean but he can't move from his pain before Sam appears to tell them Jack died.
Castiel deduces Jack has ascended to Heaven, which he detects is having distress since its gates are opened. Castiel leaves for Heaven and finds it ransacked before locating Duma who tells him that something attacked her but she doesn't know what it was and she asks to accompany him since she is afraid, which he allows. They go into Jack's personal Heaven but he is not there and Naomi appears. She tells Castiel it is The Shadow, something that makes Castiel remember his time in The Empty. Naomi tells him that he is the only angel to escape the realm and states it is after Jack because of his heritage and Castiel becomes determine to protect him. Naomi tries to get him to reconsider but comes under attack by it and implores Castiel to run. Castiel knew Jack might be in the personal heaven of Kelly Kline and his theory was correct as Kelly is hiding him from the threat. Castiel lets them know its him and shares a greeting with them and Kelly relieves him of guilt after he states he failed her and tells him that Jack is wonderful before he explains that he and the Winchesters are working bring Jack back to life, which is why he present.
After he then informs them of how the procedure goes, they are worried until he tells them what is after Jack, telling them that because of Jack's angel heritage he will be sent to The Empty, which is why he should be revived. However, Duma appears but she is revealed to be possessed by the shadow, The Shadow mentions its meeting with Castiel who attacks it but is overpowered and knocked aside. While downed, Castiel receives word from Dean that the spell is finished as he watches Jack being defeated. The Shadow prepares to claim Jack but Castiel offers it a deal, his place for Jack. A worried Jack tries to intervene but Castiel convinces The Shadow as it makes the terms for claiming him at his most happiest as it wants to make his end painful, Castiel accepts before the shadow leaves Duma who regains her body.
Afterwards, Castiel tells Jack not to tell Sam or Dean of his act, as Jack states he will keep his secret to protect her son when he gets back and he promises. Castiel leaves Kelly's heaven before he is met by Naomi, who has recovered and thanks him for his act before giving him the location of Michael as a reward. Castiel is shocked to hear this and listens to her for the answer.
During The Spear, Castiel talks with Jack and the latter appreciates his selfless act. He later joins his friends on where to find Michael and defeat him after learning of his plans to unleash his army on a city. He hears from Sam of Michael's plans to unleash a monster army on a city, disgusted at the latter's intent.
He and the others split up with him joining Dean on locating the spear of Alternate Kaia. Castiel notices Dean's mood and becomes guilty at Dean stating they have a win with no problems, which causes him to recall his deal. When Kaia is able to get the drop on Dean, Castiel tries to advance on her but Dean stops him from attacking, telling Kaia that they have come to ask for the spear, not to try to steal it. Castiel watches as Dean makes a deal with her to give them the spear, but in exchange for bring Jack to open a rift as he did with her Main Universe counterpart. Kaia tells Dean and Castiel that they can find her again the same way they did this time and then vanishes as they are distracted by a phone call from Sam.
At Michael's headquarters, Castiel is detected by the Archangel and confronted by him. Castiel attempts to attack him though he effortlessly overcomes his attacks. The Archangel drags the wounded angel to his office where Castiel watches as Dean attacks him while armed with the Spear. Castiel is relieved that it might finally end, when Dean overpowers him but behaves strangely by breaking the spear and Michael's vessel falls dead. Castiel is speechless when its revealed Michael has possessed Dean once more, having left a way to enter his body without consent. Castiel asked why he waited so long to take back control and is disgusted by Michael's desire to break Dean's spirit and locking him away to prevent his interference. Michael taunts Castiel and the rest of Team Free Will by telling them, nothing stands in his way now and his monsters are on the prowl awaiting his signal, which he soon gives with a snap of his fingers.