|“||You, celestial being, have been created to be an angel of the Lord.||”|
— The inner "programming" of an angel
After creating humans, God assigned Gadreel to protect his cherished creations in the "Garden of Eden". He then asked all the angels to bow down to humans as his greatest creation and love them more than him. Lucifer, due to the corrupting effect of the Mark, became envious, as he was God's favorite creation before humans, and saw that humans were broken, flawed, and murderous. Lucifer attempted to convince God of the flawed nature of humans, but God didn't listen. Faced with this situation, Lucifer became increasingly desperate. He went to Michael and asked him to stand with him, but Michael refused. Whereas Raphael chose to side with God and Michael, Gabriel, being unable to deal with the constant arguments, fled to Earth, posing as The Trickster, Loki. Michael and Lucifer later fought until, eventually, Michael cast Lucifer out of Heaven. Out of anger against God, Lucifer corrupted a human soul, who would later be known as Lilith, into the first demon. Lucifer then slipped past Gadreel into the garden and poisoned the Earth with his own evil, forcing God to lock Gadreel away (for thousands of years), as he failed to keep Lucifer out of the garden. God then had Michael personally cast Lucifer into Hell, specifically Lucifer's Cage. Lucifer was locked away with over 600 powerful seals, 66 of which needed to be broken for his release. A prophecy states that one day Lucifer will break free, initiating the Apocalypse, and that Michael will kill him and bring paradise to Earth.
Following the failure of Gadreel, and the fall of mankind, God left Heaven. Before he left, God picked the angel Metatron to be his personal scribe, and take down his word. He told the scribe all his secrets, and Metatron wrote them down on various stone tablets. Out of fear that the archangels would steal the information of God from him, Metatron fled to Earth, choosing to live among a Native American Tribe.
Castiel and his garrison tentatively watch the first humans hold dominion over the Earth, as God originally intended. Castiel watched events like the falling of the Tower of Babel and the destruction of Sodom and Gommorah. Castiel's immediate garrison - Anna, Uriel, Hester, Balthazar and Inias - are stationed to protect and watch the Earth. They watch and wait in silence for thousands of years, hearing nothing from God or their superiors in Heaven.
The first appearance of an angel/archangel was made in Season 2. Masquerading as the Trickster Loki, Gabriel killed three people at a college while positioning himself as the school janitor. Once Sam and Dean showed up to investigate the deaths, he began to manipulate them into fighting among themselves. Eventually catching on, Sam, Dean, and Bobby attack Gabriel, and Dean stabs him, believing him to be dead. However Gabriel was revealed to have survived, with Dean only stabbing an elaborate illusion.
Bent on both revenge and teaching Sam a lesson, Gabriel (still masquerading as the trickster) had set up a mystery spot which the boys investigated. Once there, the boys were trapped in a time loop causing the day (which happened to be a Tuesday) to repeat infinitely. Every day, Dean would die and Sam was powerless to stop it from happening. Eventually Sam discovered that Gabriel was to blame for the time loop and confronted him, threatening him and convincing Gabriel to end the cycle. Supposedly he did so, resuming the flow of time and releasing the boys. However, on the first Wednesday after the time loop Dean was killed again, seemingly permanently. Sam spent the next 6 months hunting Gabriel, intent on either bringing Dean back or killing him. Sam eventually found Gabriel who revealed to him that Dean's numerous deaths were to teach him a "lesson", and that the brothers are each other's ultimate weakness. Gabriel was apparently trying to show Sam that nothing is gained from sacrificing themselves for one another, and that the "bad guys" would always use one brother against the other. Sam continued to beg for Gabriel to bring Dean back to life and reset time, and he reluctantly did so.
In 2008, Dean was killed by Hellhounds under the orders of Lilith. While in Hell, Dean broke the first seal to free Lucifer. Castiel was sent to rescue Dean from Hell. He led a siege against Hell's defenses, along with Uriel and several other angels. Castiel successfully saved Dean, resurrecting him but he was not in time to stop him from breaking the very first seal. Castiel soon revealed himself to Dean and told him of the angels' mission to stop Lucifer from rising. On Earth, the angels tried to stop Lilith from bringing about the Rising of the Witnesses, but they failed, and another seal was broken.
When two witches prepare to summon the demon Samhain - which will break yet another seal - Castiel and Uriel are sent to destroy the town to prevent Samhain's rise. The Winchesters, however, refuse to let them kill everyone in the town, and set out to stop Samhain's summoning themselves. Unfortunately, they fail to prevent the summoning, and though they defeat Samhain, the seal is already broken.
Fallen angel Anna Milton is on Earth, as she "cut" out her grace and fell, and is in psychiatric ward. She has no memory of being an angel but can hear angels speaking in her head on "angel radio". She escapes the psych ward after demons start coming after her. After much searching, Alastair, a demon who is accompanied by two demons, finds her. Castiel and Uriel arrive, and the opposing sides face off. Uriel easily dispatches both of Alastair's guards, while Castiel is overpowered and apprehended by Alastair. Anna regains her grace, and becomes a full-blown angel again. In consequence of her consuming her grace, intense light leaks out of her eyes, and envelopes the room, destroying Alastair's vessel.
The angels manage to save a seal - in this case the attempted killings of two reapers - by tricking Sam and Dean into investigating a town where people have stopped dying. In addition, they capture Alastair. Around this time, seven angels from Castiel's garrison are murdered, and Lilith is immediately suspected.
Castiel and Uriel have Dean, Alastair's former apprentice during his time in Hell, torture Alastair to learn how Lilith is killing the angels. Alastair, however, breaks free, beats up Dean, and almost exorcises Castiel when Sam appears and - after learning from Alastair that Lilith is not behind the deaths of the angels - kills Alastair with his blood-fueled powers. Castiel later discovers that his friend Uriel is the true culprit as well as an agent of Lucifer. Uriel tries to convince Castiel to help him free Lucifer, but Castiel refuses and fights his old friend. Though Uriel gets the upper-hand, Anna appears and stabs him with an angel blade, killing the traitor.
Some time after this, Castiel learns something important and tries to warn Dean, but is captured by the other angels and taken back to Heaven, where he is tortured into obedience. It's later revealed by Zachariah, a higher ranking angel and Castiel's direct superior, that senior management intends on allowing the 66 Seals to break, in order to bring about the Apocalypse. To that end, they abduct Dean to prevent him from stopping Sam in killing Lilith, as Lilith is the final seal. Sam and Dean are Lucifer and Michael's true Vessels respectively, and would be used by the archangels during the fight. The angels believe that the Apocalypse is God's plan, and will cause everlasting paradise on Earth. It's also revealed that God has left Heaven, leaving the archangels in charge to do whatever they wish.
Castiel rebelled and helped Dean escape Zachariah, after banishing him. Castiel took Dean to Chuck Shurley, prophet who foresaw The Apocalypse coming (and who unknown to all was God in disguise). After learning Lilith's location from him, Castiel sent Dean there while he was killed by the archangel Raphael for his desertion. Lucifer was set free by Lilith's death at Sam's hands.
As planned, Lilith is killed (the last seal) by Sam, and Lucifer is freed. Zachariah is sent to claim Dean as a vessel for Michael but Dean says no to Michael, which impairs "the final charge", making Lucifer unstoppable for the remainder of season 5. Castiel, who had been killed is resurrected by God, who is revealed by the angel Joshua to still be around. Castiel rebels against Heaven and actively helps the Winchesters.
Lucifer also unleashes deadly plagues upon the world, with the intent of destroying humanity.
Throughout the season, Zachariah tries repeatedly to get Dean to say "yes", but Dean continues to refuse and eventually kills Zachariah himself. However, Michael claims the resurrected Adam Milligan (Sam and Dean's half-brother) to be his vessel.
Soon Lucifer makes contact with Sam, revealing that he is his true vessel though like his brother refuses to consent. Anna Milton attempts to stop the Apocalypse on her own by going back in time and killing John and Mary Winchester to prevent Sam's birth. She fails, however, and is killed by Michael. Gabriel resurfaces and tries to help the Winchesters kill Lucifer, but is killed himself. Throughout the season, Castiel, now a fallen angel with limited power works with the Winchesters to stop the Apocalypse.
Finally in Swan Song, Michael - in the vessel of Adam - confronts Lucifer, archangel to archangel. Dean interrupts the fight, along with Bobby and Castiel, and manages to distract the archangels long enough to reach Sam, who is serving as Lucifer's vessel. Sam briefly regains control of his body during the fight and uses his moment of clarity to throw himself/Lucifer and Adam/Michael into Lucifer's Cage, ending the Apocalypse. Castiel, though killed by Lucifer during the final confrontation, is resurrected by God again as a Seraph and he resurrects Bobby, heals Dean and heads back to Heaven to restore order as the new leader now that Michael has been imprisoned.
In the aftermath of Michael's imprisonment and God's abandonment of Heaven, the angels fall into disarray. They don't know what to do or who to take orders from. Castiel, who had rebelled against Heaven in order to help the Winchesters, returns to Heaven and starts preaching the idea of Free Will to his fellow angels. However, many of the angels can't even grasp the concept. The remaining archangel Raphael confronts Castiel and demands that he kneel and repent for his rebellion. Raphael also plans to release Michael and Lucifer from the Cage, thus restarting the Apocalypse. When Castiel refuses to go along with this, Raphael threatens to destroy him and his followers unless they submit.
Castiel reluctantly makes a pact with the new King of Hell Crowley. Crowley and Castiel go to Hell, which Crowley personally re-designed, and there they plot to open Purgatory and absorb the souls of all the deceased monsters inside. Crowley gives Castiel 50,000 souls, which he uses to initiate a war against Raphael. Castiel also pulls Sam's body out of Lucifer's Cage, but is unaware that he was unable to rescue his soul as well. Despite gaining control of Heaven's Weapons, which the angel Balthazar had stolen from the heavenly vault, Castiel's war goes badly, and he becomes more and more desperate to find Purgatory. When the Winchesters discover what he's been doing, they confront him, and he tries to convince them that he has no other choice but to follow through with his plan. When the brothers refuse to back down, Castiel breaks Sam's 'wall', a barrier put in place by Death between his consciousness and his tormented soul, allowing his horrific memories of Hell to flood his mind and incapacitate him.
Later, Castiel goes back on his deal with Crowley, and after opening Purgatory successfully, takes in all of Purgatory's souls. Unknown to him, he also absorbs the Leviathans. Castiel, utilizing/channeling the souls power essentially becoming god-like, obliterates Raphael.
Castiel then goes to Heaven, and smites every surviving angel who ever helped Raphael. He informs the remaining angels that he is their father now, and that they must be obedient children or suffer the consequences. He then returns to Earth to begin destroying everything he perceives to be evil. Eventually, realizing the error of his ways, he goes to the Winchesters and Bobby for help. He says that if he were strong enough, he'd "fix" Sam. With their aid, he manages to send the souls back to Purgatory, but the Leviathan remain.
The Leviathan take over his vessel and him, and beat up Dean and Bobby. Then, they leave, and disperse into the water supply, leaving Castiel and his vessel seemingly destroyed. However, he is resurrected yet again, and Castiel awakens without any memory of who or what he is. He goes by the name "Emanuel" and marries the human woman who found him. Dean and Meg are able to remind him of who and what he is, and he, upon re-gaining his memory, tries to save Sam - who's been driven to near insanity by hallucinations of Lucifer - but realizes that the 'wall' has completely crumbled. He then shifts Sam's "pain" (condition) unto himself. While this cures Sam, Castiel is forced to stay at the mental hospital under the protection of Meg.
Meanwhile, back in Heaven, the angels Hester and Inias have taken command of the few angels remaining. When Dean and Sam break the "shell" of The Word of God, a ting is emitted, one that only angels can hear. When Castiel hears it, he awakens, only differently; more timid, calm, and refused to fight. At the same time, Hester and Inias go to Earth to retrieve both the Word and the Prophet Kevin Tran - who has been chosen to be the Keeper of the Word. However, the Winchesters need Kevin to the stop the Leviathan and a conflict ensues between the Winchesters and the angels. The dispute ends when Meg steps in and kills Hester, after which Inias takes charge and agrees to stand down.
Castiel provides Dean and Sam with his blood for the weapon then goes off on his own. When looking for flowers and fruit (flowers come first obviously) he can't hear anything from his garrison. After a long silence, he goes to the home of the Prophet Kevin Tran and finds the entire Garrison dead or in hiding - victims of the Leviathan.
Upon Dean's request, Castiel teleports himself and Dean to the Impala, and he ultimately decides to take part in the fight. Together, the two of them sneak into SucroCorp's lab, where they find Dick Roman and another Leviathan Royce testing a batch of poisoned creamers. Cass douses Royce with Borax as Dean beheads him. He then restrains Dick Roman long enough for Dean to stab him with the Bone Of Righteous Mortal Washed In the Three Bloods of Fallen, killing the Leviathan leader, though he and Dean are transported to Purgatory in the process.
A repercussion of stabbing Dick with the Anti-Leviathan weapon, both Dean and Castiel are pulled into Purgatory. Heaven's angels are terribly reduced, leaving an unknown amount of angels. An observer and admirer of Castiel, Samandriel, takes a vessel, and contributes in the auctioning of one of the Words of God. For a full year, Castiel survived being hunted by an endless swarm of monsters while regaining his sanity before he somehow escaped.
A new group of angels, led by Naomi, revealed they rescued Castiel from Purgatory. They are keen on keeping track of developments involving the tablets containing the Words of God.
When the angel Samandriel is captured and tortured, he reveals there is an angel tablet to the demon Crowley. Naomi then orders Castiel to kill Samandriel. Castiel, without a choice and without remembering her orders, stabs him with an angel blade, killing him, after Sam, Dean, and himself rescued him from Crowley's demons. While rescuing him and hearing Samandriel being broken, Castiel remembers Naomi torturing him in a similar manner. Naomi later sends Castiel to find the Angel Tablet which is located in one of Lucifer's Crypts. With the help of Meg and the Winchesters, Castiel locates the tablet, but on Naomi's orders, tries to kill Dean. The tablet sets Castiel free and he flees with it to protect it from everyone. The angels are shown to have no luck locating him. Crowley offers a deal between himself and Naomi who he knows, but she disappears before he can even finish.
Naomi later captures Castiel and reveals that he has taken part in many atrocities throughout human history but has had them erased from his mind as he never truly follows his orders. Naomi is forced to flee when Crowley arrives with a gun capable of killing angels as the bullets are made from a melted-down angel blade. Crowley is working with the angel Ion who is disillusioned with Heaven and the angels due to what they are being forced to do. Crowley gets the angel tablet from Castiel, but after he leaves, Castiel manages to kill Ion and escape. At the same time, the Winchesters find Metatron who explains that when God left, the archangels decided to take over everything, a plan that Naomi is apparently still following. Metatron is convinced to help and rescues Kevin Tran from Crowley. Castiel later comes to the Winchesters for help, severely wounded and badly weakened by Crowley.
Metatron eventually comes to Castiel for help after learning the state of Heaven and about him from Kevin Tran. Heaven is in a state of civil war with many factions warring for control. While Naomi had been believed to be the new ruler of Heaven, she is merely one of the many faction leaders. Metatron has decided to seal up Heaven to prevent the war from spilling onto Earth and to force the angels to sit down and hash out their problems. Castiel and Metatron start the trials to seal up Heaven by killing a Nephilim, the child of an angel and a human.Metatron later revealed to Castiel that the second trial is to retrieve the bow of a cupid. Before they could complete the trial, however, Naomi's agents located the pair. Metatron was captured by Naomi and a host of angels. Castiel pursued the second trial and managed to convince a cupid to give up her bow, thus completing the second trial. Meanwhile, Naomi attempted to uncover Metatron's knowledge of the tablets, but discovered that Metatron was actually planning revenge to all the angels in heaven. The trials Metatron revealed to Castiel were not in fact the trials on the angel tablet to close heaven but a spell to expel all angels from heaven. Naomi rushes to warn Castiel and Dean. The revelation causes Naomi to regret her actions and those of all angels, telling Castiel and Dean that angels are supposed to protect humanity and lost sight of that somewhere along the way.
Trying to discover the truth for himself, Castiel traveled to Heaven, only to find Naomi dead in her office. Metatron confirmed Naomi's revelations and took Castiel's grace, completing the third part of the spell. This turned Castiel human, and caused all angels to fall down to Earth.
All of the angels have fallen from Heaven in what most humans believe to be a "global meteor shower." Some have taken vessels, but most were still encircling the world looking for vessels. Most blame Castiel for what happened and began looking for him for revenge. Desperate to save Sam, Dean prayed to all angels for help, but only Ezekiel came to help while three come looking for Castiel's location. Dean killed one with an angel blade and banished the other two while Ezekiel took Sam as his vessel to heal both Sam and himself from their injuries. At the same time, an angel named Hael approached and ultimately kidnapped Castiel, planning to possess Castiel in order to become stronger and to fit in on Earth easier. Castiel managed to defeat Hael by crashing her car, but was forced to kill her when she threatened to broadcast to all angels where to look for him.
When Ezekiel was forced to reveal himself to save Sam from Abaddon's demons. His astral projection was similar to that of previous angels, although his wings were noticeably broken. Ezekiel later revealed a faction of angels led by Bartholomew, who is a protegee of Naomi, are hunting down Castiel for revenge and gaining power. Bartholomew is shown to be using an internet preacher with a worldwide following to spread the word to say "Yes" to angels if they come looking for a vessel, allowing him and his faction to gain bodies at a fast rate. He sends angels out to look for Castiel, but after one attacks him, Castiel uses tattoos to hide himself from the angels. Bartholomew then sends out rogue Reapers to look. Dean finds out Castiel thanks to Ezekiel and rescues him, killing two Reapers along the way, but Castiel is killed. Ezekiel resurrects Castiel and later tells Dean that Castiel must leave or he will have to, as if the angels find him, they will attack the Bunker and Sam, Dean, Castiel and Ezekiel will not be able to survive a full incursion. Even though Ezekiel is slowly healing Sam, if he leaves Sam, Sam will die. So Dean is forced to tell Castiel to leave.
Castiel later calls Dean on a case. They discover the angel Ephraim, who'd taken possession of a man who had become deeply religious, so much so that he drove his wife away. Blinded by religious fervor and a desire to serve God, the man let Ephraim into his body. Ephraim began a killing spree, using his abilities of pain-detection to track down the gravely injured or emotionally despondent and using his healing abilities to heal them or his special smiting abilities to give them a quick and virtually painless death, ending their misery. Castiel was forced to kill him.
Metatron returned to Earth to speak to the angel in Sam's body, revealing that he knows the angel possessing Sam is not Ezekiel, but Gadreel. Metatron tells Gadreel he plans to rebuild Heaven and restore it to its former glory. He invites Gadreel to be his second in command, and restore his besmirched name. Gadreel agrees, but Metatron demands a demonstration of his loyalty. He wants those who could oppose him killed, and gives Gadreel a piece of paper with the first target; Kevin Tran. While Castiel is being tortured by Malachi, he learns that Ezekiel was one of the angels who was killed during the angel's expulsion from Heaven. After he escapes, Cass passes this information onto Dean. Dean decides Ezekiel must be expelled and asks Kevin for a spell that will help him speak to a Sam, while repressing the angel. However Gadreel was aware of Dean's plan and knocks him out. Gadreel then finds Kevin in the main bunker room and despite Dean's intervention, he kills Kevin and leaves with the angel and demon tablets. At the same time, the factions led by Malachi and Bartholomew go to war for rule of Heaven, something that is bad as either ruling wouldn't be a good thing.
Gadreel discovers the pop idol Corey is actually possessed by the angel Thaddeus, who tortured him and another angel called Abner during their imprisonment in Heaven. Gadreel later kills him with an angel sword on the orders of Metatron. Metatron demanding test of loyalty, gives Gadreel's another target which turns out to be his friend Abner. The angel Abner possessed an abusive man and was now living a happy family life. Dean, Cass and Crowley later track down the Impala - and Gadreel who has killed Abner. Gadreel is quickly taken hostage and Crowley begins the painful process of accessing the angel's mind. He is able to access Gadreel's "programming" and makes the angel reveal his identity. Castiel is enraged, as he views Gadreel as responsible for everything from the absence of God to the Apocalypse. Crowley offers to possess Sam, and alert Sam to Gadreel's presence, so he can expel the angel. Dean agrees, and gets Castiel to remove Sam's anti-possession tattoo. Crowley then enters Sam's mind and convinces Sam that an angel is possessing him, but Gadreel finds them. A fight ensues but Sam is strong enough and expels Gadreel from his body. Crowley leaves voluntarily. Gadreel returns to the bar where Metatron is, and repossesses his original vessel.
Castiel later learns that a third faction has developed led by an angel named Rebecca. This faction, the Penitents coexist with humanity harmlessly, but are slaughtered by Bartholomew and his followers. Castiel is captured by members of Bartholomew's faction who take him to Bartholomew who wants to ally himself with Castiel now, believing that with Castiel on his side, he can unite all of the angels under his rule. Bartholomew's faction is tracking Metatron who has appeared on Earth at least three times since the Fall, but they are also ruthless, killing any angel that doesn't join them, even harmless factions like the Penitents. Castiel doesn't agree with Bartholomew's methods and after Castiel is forced to kill Bartholomew in self-defense, many of Bartholomew's followers decide to follow Castiel in a less violent way where angels don't kill other angels anymore.
Metatron has Gadreel start killing angels that won't follow him and after an unsuccessful attempt by Sam and Dean to trap Metatron who has attained God-like powers from the Angel Tablet, Castiel amasses an army against Metatron. Both sides work on uniting all the angels against each other, with Gadreel killing Malachi and anyone else who they approach who refuses to join. As Castiel's army is larger than his, Metatron begins using suicide bombers brainwashed to believe they are acting in the name of Castiel to unite all of the angels under himself, succeeding in getting Castiel's faction to abandon him. However, this turns Gadreel against him. While Dean and Sam confront Metatron on Earth, Gadreel and Castiel sneak into Heaven to shatter the angel tablet and Metatron's connection to it to return him to a regular angel.
After being captured, Gadreel sacrifices himself to make Hannah see reason and Castiel manages to find and shatter the tablet, but not before Metatron mortally wounds Dean. Metatron confronts Castiel, not knowing he is secretly broadcasting the entire conversation over "angel radio" and reveals his low opinion of humanity and the angels, causing everyone to turn against him. Metatron is captured and locked in Heaven's dungeon. While the other angels once more turn to Castiel for leadership, all he wants to be is a normal angel again and faces the prospect of dying when his grace burns out unless he replenishes it.
Following Metatron's defeat and imprisonment, a weakening Castiel returns to Earth while the angels form their own government. According to Metatron, under Hannah's leadership, Heaven is being run better than it has been since God left. Six weeks after Metatron's defeat, Hannah approaches Castiel for help in finding rogue angels and bringing them home. Two of these angels are Daniel and Adina who wish to stay on Earth and live out human lives. Castiel is forced to kill Daniel to save Hannah, but abandons the mission to aid Sam in his efforts to cure Dean who is now a demon. Their trip is interrupted by Adina who attacks the severely-weakened Castiel and attempts to kill him and Hannah. Crowley saves them, taking Adina's grace and killing her. Crowley restores Castiel's health and power with Adina's grace in exchange for him helping to stop Dean for good. After helping to cure Dean, Castiel and Hannah continue on their mission of finding angels to return to Heaven, but an encounter with her vessel's husband causes Hannah to return to Heaven permanently so that Caroline can return to her normal life.
After Dean slaughters a group of humans under the influence of the Mark of Cain, Castiel enlists Ingrid's help to bring Metatron to Earth so he can be questioned in hopes of a cure. Metatron claims knowledge of the cure, but demands that he gets many things in exchange, leading to Dean torturing and nearly killing him for information. Castiel and Sam break in in time to stop him and Castiel returns Metatron to Heaven rather than continue to risk his life. Following this, Castiel takes up an effort to find a cure for Dean, mainly by locating Cain, the previous wielder of the Mark. Castiel's search for Cain leads him to find out that Cain is slaughtering his descendants and Castiel teams up with the Winchesters and Crowley to bring an end to the Father of Murder. Though Cain is so powerful that not even Castiel's holy abilities can harm him, he succeeds in helping draw Cain into a trap, allowing Dean to finally kill him.
Following Dean's condition worsening, Sam and Castiel decide to force Metatron to help, but Hannah refuses to let Castiel into Heaven to get him, knowing Metatron will want his freedom in exchange which can't happen. Teaming up with Bobby Singer, they raid Heaven and break Metatron out. Castiel removes Metatron's grace, rendering him human and he admits that he actually doesn't know of a cure which Castiel can tell is the truth. To stop Sam shooting him, Metatron confesses that there is some of Castiel's grace left and offers to lead him to it. Metatron leads Castiel to his grace in a library, fighting an angry Cupid along the way. However, while they search the books for the grace, Metatron reveals his true plan is to retrieve the grace and the demon tablet and escape. He stuns Castiel and retrieves the tablet, but flees when he sees that Castiel has found his grace. Castiel takes in his grace, regaining his full power and status as a Seraphim, though his wings remain broken. However, he and Sam keep Metatron's escape with the demon tablet from Dean despite worrying about what Metatron can do with the tablet and his freedom.
After getting a call that his vessel's daughter is in the hospital, Castiel discovers that some of the Grigori, long thought wiped-out, have survived and are now feeding off of human souls. Castiel and the Winchesters come into conflict with the Grigori Tamiel who had kidnapped Jimmy Novak's wife, Amelia and had been feeding on her soul for two years. Castiel is able to rescue Amelia, but she is beyond his ability to heal and she sacrifices herself to save her daughter Claire. In the fight that follows, Claire kills Tamiel with his own angel sword, but there are other Grigori out there.
Following the encounter with Tamiel, Castiel continues his efforts to save Dean from the Mark of Cain. He acts as a guard for Charlie Bradbury and Rowena as they attempt to translate the Book of the Damned to use it to save Dean. Charlie eventually escapes to get away from Rowena, but is killed by Eldon Frankenstein. Following her death, Dean goes on a revenge rampage and Castiel attempts and fails to stop him. After decoding the Book of the Damned, Castiel calls on Crowley to help gather the necessary ingredients and watches as Rowena successfully removes the Mark of Cain from Dean's arm. However, unknown to them, the Mark's removal unleashes Amara, a primordial evil that took God and his Archangels to beat. After the Mark is removed, Rowena escapes and puts Castiel under a spell that makes him attack Crowley.
Under the influence of Rowena's spell, Castiel attacks Crowley who escapes by smoking out. Still under the effects of the spell, Castiel travels to the portal to Heaven for help only to find it gone. Learning of Amara's release, Castiel prays to his siblings for help and Efram and Jonah respond and lead him to a warehouse, explaining that the angels moved the portal after Metatron's escape. However, they have no intention of taking Castiel to Heaven and instead chain him up. They torture him repeatedly for information on Metatron, refusing to believe Castiel when he correctly informs them that Metatron tricked him and escaped.
Finally, Hannah arrives and puts a stop to the torture, but is unable to heal Castiel or break Rowena's spell. Hannah informs Castiel that the alarms in Heaven have gone off for an unknown reason and Castiel informs her of the escape of the Darkness. Hannah asks him about the Winchesters location and Castiel realizes the whole thing is a trick in hopes of getting information out of him. Hannah explains that since he helped Metatron escape, most of the angels hate Castiel now and she is working under orders from the new democracy in charge of Heaven to find out what he knows. When Castiel refuses to cooperate, Efram and Jonah attempt to use a device similar to the one Crowley used to hack Samandriel and Gadreel to hack Castiel's brain. As Hannah distracts the other angels with her objections, Castiel falls back under the influence of Rowena's spell and breaks free, killing Jonah in self-defense. An angry Efram murders Hannah for her interference before Castiel kills him too. Castiel later travels to the Bunker to enlist Sam and Dean's help.
The angels later meet on Earth, aware that Amara plans to take over Heaven. They figure that their leaders won't do anything, so they have to spread the word that they unite and move against the Darkness. When three angels call on Amara to surrender they warn that each and every angel in the sky is ready to smite her with one blow. After Amara kills the angels a blast of heavenly light smashes down. To check if the Darkness survived, the angels sent Ambriel to Earth.
Later, the angels are approached by Lucifer possessing Castiel's vessel. He promises them victory in the war if they accept his help. Amara, fully recovered, strikes Heaven with a powerful wave that knocks every angel off their feet. Amara also kidnaps Lucifer for torture.
Lucifer returns to Heaven weeks later, fully healed and intent on gaining their help. The angels all gather around him armed with angel blades, showing hostility, so Lucifer switches places with Castiel, in hopes that they would listen to him. The angels disregard Castiel also, but Castiel insists that they all have their part in this war, and for Castiel, it's being Lucifer's vessel. The angels are hesitant and wish for God to personally tell them after learning he was on Earth the whole time. Castiel encourages them to help God fight the Darkness, if they so choose, which they finally agree to.
During the battle, Rowena and the witches launch the first attack, weakening Amara's vessel. Once complete, the angels create another combined smite and launch it against Amara, thus weakening her further. Their attack is followed up by the demons' own assault.
However, the battle ends in Amara's favor with God left dying on the floor and Lucifer expelled from his vessel. Convinced the world is going to end and sensing God dying, the angels lock up Heaven and choose not to grant any further assistance, as Castiel soon finds out.
Fortunately, the Darkness reconciles with God and heals him saving both the world and Heaven from destruction.
The angels are mostly vacant in the first half of season 12. We learn that in 1901, a group of angels, including Castiel, went to a house to destroy a Nephilim. The leader of the angels, Ishim, was lying to them. The alleged 'Nephilim' was a little human girl. The mother of the girl, Lily Sunder, hunted down that group of angels, killing several before the truth came out and Castiel finished it for her. Other than that, the angels have been heard over angel radio after the archangel, Lucifer, got Kelly Kline pregnant.
The main goal of the angels is to get rid of the unborn child, and two angels have already attempted to execute Kelly, only to be stopped by Dagon. The angel Joshua has also decided to take charge of Heaven during the course of this mission, and according to the angel Kelvin, if Castiel helps, he will be forgiven by their siblings and accepted back into Heaven.
The mission led by Joshua is a failure and all angels who partook in it, aside from Castiel, are killed by Dagon.
Three angels - Conrad, Lily and Miriam - set out to capture Lucifer's newly born son Jack. The three are hindered in their quest by Dean and Sam Winchester, with Conrad and Lily getting banished and Miriam killed.
During The Rising Son, Lucifer and Mary encountered the alternate version of angels in Apocalypse World who are more soldier like. It is revealed by the Angel Commander that Michael killed this world's Lucifer and is the ruler of Apocalypse World. Lucifer kills the angels sent after him but Michael appears and learns of Lucifer being from another world and attacks him, ending with Lucifer being captured by the latter.
During Patience, the essence of Castiel awakes in an unknown realm and is left confused by his location.
In The Big Empty, Castiel learned from The Shadow that after death, angels along with demons are sent to The Empty to slumber for eternity. Castiel was shocked to learn that every angel who ever died was in the realm. Castiel also became the first angel to ever escape after he annoyed the entity by staying awake and demanding his release.
|“||Castiel, the angels... Our numbers were greatly diminished after the fall. No one's made new angels since the dawn of Creation. We're going extinct. You would need a powerful force to make more of us.||”|
It was seen in War of the Worlds, Michael has made plans to invade the prime Earth after seeing it in the captured Lucifer's mind and has his followers open a Rift using Lucifer's grace. However, it backfires as Lucifer uses it to escape back to his world. On Earth, Castiel learns from an angel named Duma that after the Fall the number of angels has drastically decreased and they are close to extinction. They need Jack to use his powers to replenish their numbers as God has left. Castiel refuses to help them enslave Jack and fights them but is nearly killed until Lucifer makes his appearance and they retreat. Lucifer informs Castiel of Michael before they get captured by Asmodeus.
The angels continue to try and procure Jack as seen in The Bad Place. After Jack visits a Dreamwalker named Derek Swan for help in opening a rift to Apocalypse World, two angels looking for Jack visit Derek soon afterwards and torture him for information about Jack. After Derek directs them to Kaia Nieves, another dreamwalker, the two angels smite him to cover their tracks. However the Winchester's find out about Derek's murder and use it to find Jack who is attempting to rescue Mary from Michael in the Apocalypse World. The two angels who interrogated Derek find Kaia and abduct her to use as a bait to lure Sam, Dean and Jack to them. After they arrive to save Kaia, the female angel attempts to get Jack to come with them but Jack refuses and the angels attempt to kill the Winchester's and take Jack by force. After banishing the female angel, Jack kills the male to stop him from killing Dean. Near Sioux Falls, the female ambushes Sam, Dean, Jack and Kaia and chases them into the Larsen Bros. Shipyard with five other angels as backup. As Sam, Dean, Jack and Kaia flee onto an abandoned cargo ship, Sam sets up warding to keep the angels out but they perform a ritual to gradually destroy the sigils so Jack and Kaia decide to open a rift to Apocalypse World. As the angels are close to breaking through the warding, Jack and Kaia finally open a rift disintegrating the attacking angels in the process and briefly sending the Winchester's to the Bad Place and stranding Jack in the Apocalypse World where he is later captured by Michael.
In Various & Sundry Villains, Lucifer and Castiel make their escape but comes to blows, which leaves both wounded.
During Devil's Bargain, Lucifer claimed that since he was around to witness the creation of every angel by God, he not only knows how to build an angel, but also how to restore a fallen angel's wings.
After offering to create new angels and restore the wings of the current angels, Lucifer was made the undisputed ruler of heaven. It is also revealed Gabriel is still alive and held captive by Asmodeus who has started to prepare for the invading Michael.
In Good Intentions, Alternate Bobby mentioned the angels of Apocalypse World were commanded by Michael to exterminate the human race. The remainder of humanity is relegated to small colonies that are targets for any angels that locate them. Angels are known to "dive-bomb" human colonies and wipe out every single person they can find. Human survivors are often left sporting various injuries and are protected by the remaining hunters in the world. After escaping Michael's captivity, the Nephilim Jack decided to fight against Michael and the angels.
During Bring 'em Back Alive, Dean sees the tyrannical rule of the angels in Apocalypse World with them imprisoning or killing humans in Michael's name. It was also mentioned that Jack is now waging war against the angels who are rounding up resistance leaders. On Earth, Lucifer struggles with his new role, eventually admitting to Anael privately that he can't actually do the things he said. He subsequently abandoned Heaven after deciding to find his son. Likewise, a rejuvenated Gabriel wanted no part in helping in the conflict with fighting the Alternate Michael.
|“||Well then, let me make this divinely simple for you. There are a grand total of nine angels in Heaven - present company included - and one or two on Earth, and... that's all. We are the last men, women, and divine waves of light still standing.||”|
— Naomi explaining to Castiel how few angels there are
In Funeralia, Castiel visits Heaven and requests for help with finding a still living Gabriel and reveals to them that he needs their help in battling an Alternate Michael both of which surprise them. To Castiel's shock, he meets Naomi in Heaven, alive after her apparent death years earlier. Naomi explains the gravity of the angels' situation: at the time of their conversation, there is only nine angels in Heaven, including Naomi and Castiel and one or two on Earth "and that's all." With less than a dozen angels left alive, Heaven is running out of power and the angels will burn out with it. The angels are unable to leave Heaven without it crumbling and releasing all of the souls stored in it upon the Earth. The angels' only hope is to find Gabriel who can stabilize Heaven otherwise they don't have much time left. After informing Castiel of the situation, Naomi accompanies him back to Earth and then seals the portal until the situation is resolved one way or another.
in Unfinished Business, Gabriel is shown to hunting a group of Demigods who sold him. After killing one of them, Gabriel senses the Witch, Rowena MacLeod using a tracking spell on him. Realizing that the Winchester's are looking for him, Gabriel goes to a hotel where they are staying to see if they have any more of his Grace as he drained it killing Asmodeus and it has only just started replenishing. The three are ambushed by the two other demigods who are there to capture Gabriel. After killing one of them and Scaring away the other, Gabriel explains that he is hunting down the demigods and their father Loki in revenge for selling him to Asmodeus. The Winchester's agree to help Gabriel kill the other demigods if he will help them in battling Michael, which he agrees to. After killing The remaining demigods Sleipnir and Loki, Gabriel moves on from his past as a Trickster and decides to help them save Mary and Jack as well as battling Michael.
During Beat the Devil, Gabriel captures Lucifer who was shocked his brother was alive. Gabriel traveled to Apocalypse World with the Winchesters to save Jack, he was also made aware of Heaven's state. Lucifer soon learns of his son's location and decides to find him, he resurrects a recently killed Sam after draining the grace from several of Michael's soldiers.
In Exodus, Gabriel and Lucifer have sided with the Winchesters against Michael killing several attacking angels such as the Road Attackers and Arthur and Charlie's Captors along the way. An exodus of humans through the rift is made, Michael soon arrived at the sight where he overpowered Lucifer in a brawl and killed Gabriel after a short fight. However, Michael was distracted from crossing as the rift would close on him, leaving him with a wounded Lucifer, who Sam kept from going through the rift to keep him from influencing Jack. Lucifer soon broke a deal with Michael, he would give him the ingredients to create another Rift, on the terms of Lucifer obtaining his son and Michael conquering the world.
In Let the Good Times Roll, Michael and Lucifer make it to the main universe. While Lucifer finds Jack in a forest and offers to take him on a journey to outer space, Michael attacks the Winchesters at the Men of Letters Bunker, and incapacitates Sam and Castiel before turning on dean, but while Michael is in the process of killing Dean, Sam prays to Jack who attacks Michael and uses his powers to damage his vessel, leaving him severely weakened. Dean and Sam expose Michael and Lucifer's deal to Jack as well as Lucifer's murder of Maggie; one of the refugees from Apocalypse World. While Lucifer denies these claims at first, Jack telepathically forces Lucifer to admit the truth which confirms Lucifer was the one who killed her. Enraged, Jack immediately turns against Lucifer and effectively disowns him as his father. Deciding that if he can't have Jack, he only needs his power, Lucifer takes Jack by surprise with an Archangel Blade and extracts and Consumes his Grace leaving jack powerless and Lucifer much stronger than he ever was before. Lucifer then kidnaps Jack, and Sam when he attempts to save Jack. While Lucifer decides to force Sam and Jack to kill each other and then destroy everything in The Universe, Dean makes a deal with Michael in order to defeat Lucifer once and for all; Dean agrees to act as Michael's vessel while they are fighting Lucifer but with Dean in control.
As Jack attempts to sacrifice himself to give Sam a chance to live, Dean teleports into the church where Lucifer has Sam and Jack and using Michael's power kills Lucifer. As Sam, Dean and Jack celebrate Lucifer's death, Michael takes full control over Dean and departs in order to begin his own reign of terror.
In Byzantium, after Jack died due to his lack of grace causing his body to crumble, his Soul ascended to Heaven but The Shadow, the being that rules The Empty, the realm where angels and demons are sent after death, was able to sense his death. Wanting revenge on Castiel for waking him up, The Shadow invaded Heaven to claim Jack as its property. The Shadow broke through Heaven's gates and attacked the remaining angels, apparently incapacitating at least one of them. In the aftermath of the attack, "angel radio" begins playing a distress signal, causing Castiel who is working with Sam and Dean to revive Jack to go to Heaven to find out what's going on and to do his part in reviving Jack. He finds two angels on the floor of Heaven, Zuriel, who shows no signs of response, and Duma, who wakes up, somewhat weakened and confused. Castiel explains, that he is in Heaven for Jack, and Duma, scared of being left alone asks him to let her go with him.
They arrive in Jack's heaven but he is not there. Naomi arrives and explains that the angel half of Jack's soul allowed him to realize he was in Heaven. She explains that Heaven is under attack from The Shadow, while reminding Castiel of the entity that wants to take Jack to the empty. She reveals Castiel is the only angel to ever escape the realm and how she wants to give in to the entity's demands, as it has threatened that Heaven will fall if they don't, and attempts to persuade Castiel to help her. After a moment of consideration, Castiel refuses. Naomi attempts to get Castiel to reconsider but the entity latches itself into her and begins to possess her, causing Castiel and Duma to run.
After seeing Naomi being consumed, Castiel becomes even more determined to find Jack and get him back to Earth before the entity further effects Heaven. He deduces that Jack is in Kelly Kline's Heaven and leaves with Duma to find him. The two arrive in Kelly's Heaven and split up to find Jack. Castiel finds Jack in a house with Kelly, and convinced Jack to come back to earth. As Castiel prepares to pull Jack's soul into his body, Duma arrives and is revealed to be possessed by the Shadow. The Shadow attempts to take Jack, but Castiel realizes that he is who the Shadow really wants, and attempts to convince it to take him instead. The Entity agrees but wants to wait until Castiel finally allows himself to be happy. Castiel accepts and The Entity releases it's hold on the angels and departs back to the empty, allowing Castiel to resurrect Jack. As a reward for saving Heaven, Naomi gives Castiel, the archangel Michael's location.
During The Spear, Michael has assembled a large army of monsters enhanced with his grace and prepares to launch a full scale invasion. Team Free Will attempt to gather ways to defeat him, such as collecting the Hyperbolic pulse generator and her spear. However, Michael anticipated the strategy and destroys the sphere after defeating Sam and abducting Jack. Sam recovers and slaughters the monsters in Michael's fortress, while Dean and Castiel obtain the spear. Armed with the weapon capable of killing Michael, they confront him. Fighting the Archangel proves fruitless, as they are tossed aside or wounded but Dean nearly kills Michael with the spear. However, Michael possesses Dean again, having left a way to enter his mind without consent. He soon destroys the spear while revealing his ploy to break Dean's spirit as well to rid any attempt to kill him. Michael then unleashes his monster army on the city.
As of Nihilism, Michael taunts his enemies while torturing them but his arrogance allows them to catch him off-guard and capture him. Michael is undaunted and his forces come to rescue him, while Sam summons a Reaper to appear. Jack and Castiel can't see the reaper Violet, though Michael notices her presence and taunts her about locking Death away and the enslavement of her kind in his world and she is disturbed by this and taunts his situation. After they are transported to the bunker. Using a mind-link device, Sam and Castiel enter Dean in an imaginary bar with Pamela Barnes and a loop of the same event to occupy him. Soon Castiel and Sam get through to Dean who realizes the situation, just as Michael appears (in form of Dean). The group realize he is powerless in Dean's mind and stalling until his forces retrieve him. With this knowledge, they attack the Archangel. While Michael fights the trio, Michael's monster army invade the bunker and start to slaughter the hunters. Seeing this, Jack taps into the Enochian magic keeping him alive to destroy the monsters. While in Dean's subconscious, Michael gains the upper-hand over his enemies before mocking them on trying to get him to evacuate Dean's body since it might cause physical repercussions on Dean. Hearing this, Dean decides to not eject him but keep him locked away. With help from the others, Dean puts Michael behind a locked door while he regains control of himself. Because of his imprisonment, Michael's monster army are left in disarray and scatter, stopping the threat. In Dean's subconscious, Michael continuously bashes on the locked door and screams to be released as Dean struggles to keep him trapped but worries over his control. Billie appears to Dean and notes on the Archangel bashing around in Dean's mind are keeping him occupied though warns Dean that Michael most likely won't stay trapped for long. She also gives Dean a way that defeats Michael and protects the world from him.
It is shown Ouroboros, Michael is still trapped in Dean's mind and continues to struggle at getting free. After Dean is incapacitated, Michael escaped Dean's mind but rather than possess Dean again, he took Rowena MacLeod as a vessel to get revenge. Michael nearly killed Team Free Will but Jack intervened and once again tapped into the power of his soul and battles with Michael who taunts Jack. Jack is able to withstand Michael's attacks and exorcises Michael from Rowena. As Michael swirls above everyone in a cloud of white light, Jack raises his arms and declares that the Archangel won't hurt anyone ever again. Jack then incinerates the archangel away before consuming his grace.
Jack announces that Michael is dead and reveals that Michael's grace has fully restored Jack's own powers as a Nephilim.
In Game Night, Nick sought to become one with Lucifer again and aligned himself with demons. Devising a way to resurrect Lucifer, Nick abducted and later used the prophet Donatello Redfield as a way of speaking to Lucifer. Still awaken in the realm, Lucifer told Nick to resurrect him that his blood was needed. Nick allowed himself to be captured and requested to speak with Jack. Nick antagonized Jack enough to get a sample of his blood. Nick used Jack's blood along with a ritual to open a rift to the empty. Nick was about to consent to possession but Jack appeared and sent his father back to his prison of nothingness. Jack then burned Nick to death, to forever cease his attempts to bring Lucifer back.
In Jack in the Box, Duma, has usurped Naomi status as the ruler of heaven and had her imprisoned. She persuades Jack to her side and has him come to Heaven. Duma establishes a reign of terror by having Jack kill non-believers and using her authority to threaten the other angels. She also tells Jack that he is needed to create new angels and he does so by taking a human soul out of its body and "forging" them to become one. Though it seems the angels numbers were slowly increasing, Castiel had been notified of what was going on by another angel and returned to Heaven to stop Duma's plans. Castiel was forced to kill her after she made a threat against Mary and John's souls.