|“||We're family. We need you... I need you.||”|
Having spent four painful months in Hell (40 years in hell years) after being dragged there by relentless hellhounds, Dean is miraculously rescued by the angel Castiel who later tells Dean "I'm the one who gripped you tight and raised you from perdition." This rescue mission marked Dean's left shoulder with the handprint of the angel as well as healing his body from the hellhound.
Initially, Dean suspected Sam as his deliverer, but when this proves to be wrong, the brothers, with Bobby Singer's assistance, seek the help of a psychic, Pamela Barnes. From her the brothers learn of the angel's name, although seeing Castiel's true visage resulted in her eyes being burnt out of her skull. Prior to this unfortunate event, Castiel had tried to communicate with Dean, but his true voice is beyond a human being's capacity to hear and thus, failed to establish any meaningful contact.
|“|| Who are you?" |
"Yeah, I figured that much, I mean what are you?"
"I'm an Angel of the Lord."
"Get the hell out of here. There's no such thing."
"This is your problem, Dean. You have no faith."
In Lazarus Rising, Castiel first physically appears when Dean summons Castiel to a barn where he and Bobby Singer have all kinds of traps around the room; however, the traps and guns that Dean and Bobby use have no effect on Castiel. Dean asks Castiel what he is, Castiel answers that he is an angel of the Lord.
Dean initially refuses to believe this, though he eventually comes around after seeing Castiel's Angel Wings, to his shock. Castiel told Dean he was resurrected as an order from God who has work for him.
In Are You There, God? It's Me, Dean Winchester, Dean still can't believe Castiel is really an angel before Bobby and Sam tell him just to accept it and be thankful he's alive. Castiel is next seen when he comes to Dean after the rising of the witnesses. Dean asks why the angels didn't come to help, as Castiel responds by saying angels have better things to do than "perch on your shoulder". When Dean continues to be rude, Castiel loses his temper, and tells Dean that, he should show him some respect because as Castiel was the one who took Dean out of Hell, Castiel can just easily change his mind and throw him back in. Castiel soon reveals the reason that angels are back on Earth because they are trying to prevent Lucifer's liberation of his cage.
Castiel comes to Dean later on and says, "You have to stop it." He sends Dean to the past (In The Beginning), leading Dean to assume that he has to kill the Yellow-Eyed Demon. When he fails, and in fact indirectly assists in the future being set, Castiel takes him back to the future, and uses the experience as an example of destiny. Castiel reveals that Dean really needs to stop Sam or the angels will. Dean questions before he gets Sam's location and finds him using his powers, understanding Castiel's warnings.
In Metamorphosis, Dean gave Castiel his nickname "Cass" when telling Sam how he knows of his usage of his powers. Dean also understood that Castiel was serious in stopping Sam after he sees the dark path.
In It's the Great Pumpkin, Sam Winchester, Castiel comes to Dean again with Uriel, Dean stops Sam from shooting him and lets him know who he was. Castiel tells Dean they plan to destroy the town to protect the seal, and that he and Sam should vacate. Dean is outraged that they are even considering the plan, and tells them he's not going anywhere, and that he'll stop the seal from breaking himself. After Dean begs him for time, Castiel permits it and the brothers go. At a park, Castiel reveals to Dean that their true orders were to follow Dean's commands, much to Dean's surprise. In the same conversation, Castiel admits to Dean that he has doubts about the orders of Heaven, and tells the older Winchester that he doesn't envy Dean's fate. Dean gets a new perspective of Castiel and sees he is not uptight like he thought.
|“||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 honesty to Dean
in It's the Great Pumpkin, Sam Winchester
The next time Dean sees Castiel is near the end of I Know What You Did Last Summer, he asks if they were there to help since they have demon problems. He gets worried when the angels states they have come for Anna Milton.
During Heaven and Hell, Uriel mentions Castiel likes Dean which is why he couldn't confront him in his dream. Despite Castiel being part of the team coming to take and kill Anna, Dean saves Cass from Alastair. Castiel repays him by stopping Uriel from attacking Dean.
They meet again in Death Takes A Holiday, when Alastair tried to attack Dean but Castiel saved him and managed to capture Alastair. Castiel explains that he pretended to be Bobby to send the Winchesters after the seal. Dean protested that he could have ask for help but Castiel that Dean wouldn't have helped and they argue about the reaping of people in town.
In On The Head Of A Pin, Castiel recruits Dean to help them find out who is killing angels. They want Dean to torture Alastair for information. When Dean begs Castiel not to make him open that door, he notices Castiel taking orders from Uriel before Dean asks to speak with Castiel alone. The angel admits that he's been demoted, primarily due to his growing affection for Dean. Castiel tells Dean he wishes he didn't have to ask him to do this, but it is necessary. Castiel manages to talk Dean into doing the torture, but clearly regrets it. When Alastair overpowers Dean, Castiel comes to Dean's rescue. Castiel is also overpowered, but is saved by Sam.
Castiel stops by Dean's hospital room and talks to Sam a bit before investigating why the devil's trap broke. Castiel then talks to Dean. By the end of the conversation, Castiel has admitted that it was Dean who began the breaking of the seals, the fall of a righteous man in Hell being the first of the seals.
In The Monster at the End of This Book, Castiel stops Dean from attacking Chuck Shurley by explaining he was a Prophet. Later, Dean prays and Castiel appears while praising Dean for doing so since he is developing faith. Dean asks for Castiel's help for the threat of Lilith coming for Sam but Castiel tells Dean he can't intercede. Hearing this, Dean tells Castiel to never ask for help from him again and tries to leave however, Castiel slyly goes into great detail about exactly why he can't help by giving Dean the knowledge necessary to stop Lilith. Grateful, Dean thanks Cass who wishes him luck in his endeavor.
Although Castiel finds out something and attempts to get this information to Dean, unfortunately Castiel is dragged back to heaven in The Rapture. When he returns, he tells Dean that he does not take orders from Dean. Dean is not sure how to deal with Castiel's new attitude. But he still asks for help when Sam is detoxing from demon blood. Castiel makes Dean swear himself to the service of heaven and makes him wait till they call him in When the Levee Breaks.
In Lucifer Rising, Zachariah calls on Dean, and he later finds out that the angels don't intend to stop the breaking of the seals. Castiel is clearly conflicted about the revelation, and is unable to look Dean in the eye. Castiel refuses to allow Dean to see Sam, and traps Dean in the Beautiful Room. Castiel returns later when Dean tries to call Sam, notifying him that he's "outside his service range."
When Dean asks Castiel why he came, Castiel attempts to mend fences. Dean responds by punching the angel (though this hurts Dean's hand more than Castiel's face). When Dean demands to know why they would do this, Castiel tells Dean, "I see nothing but pain here! I see inside you — I see your guilt, your anger, confusion... in paradise, all is forgiven. You'll be at peace. Even with Sam." Dean is shocked by this and tells Castiel to shove it. Dean asks Castiel what happened, and reminds him that he was going to help him before. Castiel asks what Dean would have him do. Dean tries to talk him into helping him, but Castiel refuses since its rebellion, though it's plain he's anything but content with his decision.
Castiel ultimately decides to help the Winchesters, and comes back. He helps a surprised Dean escape by banishing away Zachariah, then tells Dean that Lilith is the final seal, and that they have to stop Sam from killing her. He transports them to Chuck Shurley's home to find the location of Sam and Lilith, but is attacked by Raphael, the archangel in charge of protecting Chuck. He transports Dean to stop Sam and makes his final stand against Raphael.
In this season, Castiel has rebelled against Heaven and sides with the brothers to stop the Apocalypse. His friendship with Dean truly develops as they work closer in fighting off their enemies. Dean also begins to see Castiel as part of the family.
|“|| You know, it's kind of funny, talking to a messenger of God on a cell phone. It's, you know, like watching a Hell's Angel ride a moped." |
"This isn't funny. Dean. The voice says I'm almost out of minutes.
— Dean and Castiel
in The End
In Sympathy for the Devil, Dean and Sam go to find Castiel but discovered he was killed, which shocks them. Dean later uses a banishing seal which he states he learn from his friend Cass.
Castiel is resurrected by God (it is later confirmed) and comes to Dean's rescue when Zachariah attempts to force Dean to say 'yes' to Michael. Cass makes Zachariah return Sam and Dean to normal, and scares the angel off. When Dean questions how Castiel could be there, Cass admits that he's just as confused as they are, and leaves but not before using his power to carve Enochian sigils into Sam and Dean's ribcages, hiding them from all angelic beings, including himself.
Castiel briefly returns, in Good God, Y'all, to ask Dean for his amulet, as it apparently has the power to find God. Dean initially refuses and mocks Castiel's plan to find God. Castiel quickly loses his temper, and tells Dean under no uncertain terms that after all he, Castiel, has done for the Winchesters, he can keep his opinions to himself and give him the amulet.
In Free To Be You and Me, Castiel and Dean team up to look for Raphael, the archangel who killed Castiel. When asking for Dean's help, Castiel tells Dean that Dean is the only one who will help Castiel, implying that Dean is the only friend Castiel can trust. Castiel also has Dean come to ensure no harm is caused since Michael requires Dean to be his vessel. They first hit the police station and question the policeman who witnessed the archangel. Castiel mentions angels and demons but Dean quickly covers for them. They find Raphael's empty vessel and Castiel gets ready to face him, though he admits that the confrontation is likely to end with him dead.
While waiting for the showdown, Dean takes Castiel to a brothel so Cass won't "die a virgin". Dean, entirely in his element, is amused at Castiel's clear terror and discomfort at their surroundings. Dean attempts to set Castiel up with a young prostitute, but it ends badly when Castiel assures the woman that it wasn't her fault her father left, terrifying and enraging her. Dean and Castiel both hurry out, though Dean is in stitches over the situation.
Castiel and Raphael confront each other later, with Raphael telling Castiel and Dean that God is dead. Castiel refuses to believe this, and leaves the angry Raphael who is trapped in a ring of holy fire. Dean approves of Cass' taunts, as they leave the scene. While Dean attempts to cheer Castiel up, he ultimately runs him off by blustering that he enjoys being alone, having parted ways with Sam earlier.
Castiel continues searching for God and helping Dean.
During The End, Castiel calls Dean for his location and Dean was amused by his ineptness with a phone before he sets an appointment for him to retrieve him. That night, Dean was sent to an alternate world in the future by Zachariah and met a hippie Castiel. After Dean was sent back, Castiel rescued Dean from his brother and told Dean they had an appointment as Dean appreciated the rescue.
In The Song Remains the Same, Castiel agreed with Sam and Dean's wishes to time travel to save their parents from the rogue angel Anna Milton. Dean was worried at the pain it caused Cass and let him rest. Dean also called Cass a more friendlier angel than Anna, when talking to his mother. At the end, Dean once again helps Cass after he returns to present in his weakened state. Dean also labeled himself, Sam and Castiel as Team Free Will.
During a case in My Bloody Valentine, Dean and Sam are working on leads them to hearts with Enochian sigils carved on them, Dean calls Castiel in for assistance. While they initially believe that a rogue cupid is killing people, the true culprit, Famine, affects Castiel through his vessel, Jimmy Novak, who apparently has a craving for hamburgers. Castiel stuffs himself throughout the episode, much to Dean's disgust, and asks Dean why he hasn't been put under Famine's curse. When Dean explains that he doesn't deny himself anything, Castiel asks, "So you're just well-adjusted?" The original plan to kill Famine was to send Castiel in; however, this ends badly when Castiel is distracted by a slab of raw ground beef. Later, after Famine is incapacitated and Sam is locked up to go through detox, Castiel attempts to comfort Dean, though it doesn't appear to work.
During Changing Channels, Castiel searched for Dean and Sam while they were dealing with The Trickster. Dean was worried when Castiel was teleported by the latter. When Castiel returned battered and bloodied, Dean questioned him on where he was held as Castiel tried to warn him about the threat. After the trickster appeared, he flung Castiel away and banished him once he greeted him and Dean was angry at this. When he and Sam got fooled by the trickster, Dean worried about Cass' location before he discovered the trick. Dean soon realized Castiel's warning and the trickster's familiarity with him was a sign that the latter was an angel. After their suspicions were confirmed with the trickster being the archangel Gabriel, Dean forced him to bring Castiel back after threatening to pour holy oil on his vessel when he was trapped in a ring of holy fire. Gabriel complied and Dean asked him if he was okay as Castiel confirmed it.
When Dean and Sam go to Heaven in Dark Side of the Moon, Castiel asks them to look for Joshua, as he may know where God is. They find Joshua and find out that God had help them before by saving them and resurrecting Cass as well learning he knows about Earth's problems but simply doesn't feel he should get involved. This revelation hurts Castiel, who renounces his faith in God and disappears.
Following that, in 99 Problems, Castiel arrives on the scene drunk, short tempered, and bitter. He and Dean later have a heart-to-heart about poor fathers.
In Point of No Return, Dean attempts to say yes to Michael, which horrifies and enrages Castiel who helps Sam take Dean to Bobby's house. They try to change his attitude before Cass goes to retrieve the resurrected Adam (Sam and Dean's half-brother) who is suspected to serve as a replacement vessel for Michael. With this added problem, they lock Dean in the panic room of Bobby's basement to stop him from leaving. The feelings of betrayal come to a head when Dean escapes Bobby's home by banishing Castiel away and attempts to contact the angels. After a man prays to angels for Dean, Castiel appears and beats Dean within an inch of his life, venting his frustration. He later goes on a suicide mission, stating that he would rather die than watch Dean crumble and fail.
Castiel later returns in Two Minutes to Midnight and apologizes to Dean for not having more faith in him. Dean forgives Cass, and they reconcile. However, Castiel admits that, technically, he is human, having depleted his "batteries" during his suicide mission. Despite this, Castiel still comes to Dean and Sam's rescue and cuts off Pestilence's finger.
In Swan Song, Castiel is shockingly human, displaying more emotion than ever. He appears during the fight between Michael and Lucifer, distracting them by throwing a Molotov cocktail of holy fire at Michael. This allows Dean to try and get through to Sam, though it ends with an offended Lucifer causing Castiel to explode which horrifies Dean.
The angel is brought back after the battle, "new and improved", and heals Dean and resurrects Bobby. Dean suggests that God wants Castiel to be the new leader of Heaven, though they part ways on a tense note.
In this season, Dean and Castiel's friendship becomes strained, due to the war with Raphael, Castiel's allegiance with Crowley and Sam's soulless nature.
|“||Dean and I do share a more profound bond. I wasn't going to mention it.||”|
in The Third Man
When reuniting with Sam, Dean wondered if Castiel was behind it but didn't get an answer, he was proven right later.
Castiel comes when Dean calls him in The Third Man. He mentions in this episode that he has more profound bond with Dean than Sam. Castiel helps Dean figure out it is the Staff of Moses doing the killing and the trail leads to a rogue angel and friend Balthazar. Castiel also mentions that he needs the stolen weapons of Heaven back due to a civil war in heaven against the archangel Raphael.
Dean calls Castiel again when he's worried about Sam, but Castiel refused to answer unless it was connected to the fight he and Dean had which angered Dean. When Castiel does show up, he dismisses Dean's theory that Lucifer still inside Sam. Castiel promises Dean to make some inquiries after telling him that he, Castiel, doesn't answer Dean's prayers when they're connected to Sam because he doesn't know how to help.
Dean later calls Castiel to check on what's wrong with Sam Family Matters. Castiel reaches into Sam, and discovers that he doesn't have a soul, and explains that whoever brought Sam back left Sam's soul behind in the cage with Michael and Lucifer. When Dean questions whether soulless Sam is even still "Sam", Castiel admits that that's a good question.
In Caged Heat, Castiel exhibits more human urges, inadvertently watching porn, and later passionately kissing Meg, both to Dean's discomfort. Castiel warns Dean that bringing Sam's soul back could permanently damage the younger Winchester psychologically, but Dean remains firm on retrieving the soul. Castiel is banished with a sigil when they lay siege to Crowley's warehouse, but later returns with Crowley's bones, which he promptly incinerates when Crowley admits he can't retrieve Sam's soul from the cage. Later, when Castiel admits to Dean that he is on the losing side of the civil war in Heaven, Dean assures his friend that if he needs help, all he has to do is ask.
When Sam gets his soul back, Dean calls Castiel to check on him. When Dean questions Castiel on whether or not Sam will wake up, Castiel is curt with him, and berates Dean for not listening to him. When Dean reacts defensively, Castiel angrily tells him that Sam's soul felt "as if it was skinned alive", and tells Dean that if he wanted to kill his brother, he should have done it outright, making his stance on the matter clear.
When Castiel and Balthazar go back in time to stop the Titanic from sinking, Atropos—one of the three Fates—forces Castiel to capitulate and fix the timeline by threatening the Winchesters. Castiel even threatened Fate if she did so. Atropos then counters her promise by making her sisters go after them instead, which forced Castiel to prevent Balthazar from killing her and comply. Castiel also ensure they keep their memories of the event but doesn't tell Dean or Sam the real reason for going back in time; while he really sent Balthazar so that they would have more souls for the war, he allows them to believe that Balthazar simply didn't like the movie, or Celine Dion.
Later, the Winchesters find a way to kill Eve, using the ashes of a phoenix. However, their call for Cass is answered by his lieutenant, Rachel, who promptly loses her temper with them after they insist on speaking with Castiel. Despite her passionate words on his behalf, Castiel appears and dismisses her, much to her chagrin. He agrees to help them go back to the Wild West, and is the first to question Dean's choice of dress, asking if wearing a "blanket" was customary.
When the Winchester's search for Eve rapidly proves fruitless, Bobby suggests that Dean call Castiel. However, Castiel admits that he's had no luck either. When the Winchesters decide to track down a monster that is loyal to the cause, Castiel finds Lenore, a vampire that has had run-ins with the Winchesters before. After she tells them what she knows, she begs them to kill her, because the call of the Mother is forcing monsters to give into their baser natures. While the Winchesters are both reluctant, Castiel obliges. When they go to the town Lenore told them the Mother was in, Castiel is made powerless by her, much to Dean's irritation.In The Man Who Would Be King, Castiel's betrayal is slowly becoming known though Dean does not want to believe it, and remains desperately loyal to his friend. In the prequel part of the episode, Castiel attempts to explain freedom to the angels (in hindsight, he describes the experience as being comparable to teaching poetry to fish, and cynically states that he should have told them that "Freedom is a length of rope. God wants you to hang yourself with it"). Raphael is less than enthused, and demands that Castiel show his support, though Castiel refuses when Raphael announces his intent to restart the Apocalypse. Castiel almost goes to Dean for help, but ultimately decides not to drag his friend into the mess, rationalizing that Dean has been through too much already. Crowley appears and, playing on the angel's new sense of pride, manages to strike a deal with Castiel: his help, and 50,000 souls upfront, in exchange for half the souls of Purgatory. Castiel agrees out of desperation, and while Crowley insists that keeping the Winchesters alive is dangerous, Castiel refuses to kill them, still considering himself their guardian angel. However, during this time, Castiel takes to spying on the Winchesters and Bobby, and later betrays this fact by referencing part of a conversation he'd overheard. This leads the others to realize that he is not to be trusted, and they capture him in a circle of holy fire. After it is confirmed, Dean takes this betrayal the hardest. He also learns it was Castiel who brought Sam back from the cage but is distrustful since he may have brought him soulless on purpose. Despite this, Castiel has Dean and the others run when Crowley shows up. Later, Castiel goes to Bobby's in an attempt to explain his actions, but refuses to back down, even when Dean threatens to fight back.
Despite this, Castiel still helps Dean in Let It Bleed. When Dean is about to be killed by a demon he's interrogating, Castiel steps in and saves him. Dean is still hurt by Castiel's betrayal, and reacts with hostility. Castiel tells Dean that he too considers them to be family, and tells Dean that after all he, Castiel, has done for the Winchesters, Dean should trust Him. Even when Dean says he can't, Castiel tells him that he will find Lisa and Ben, who have been kidnapped by Crowley. They part on a hostile note, with Dean telling Castiel that he doesn't want his help. Later, Castiel comes by Lisa's hospital room, and despite Dean's exhausted hostility, heals Lisa without prompting. Dean, though grateful, states that it doesn't change the situation, a statement that Castiel regretfully agrees with. Dean asks for one more favor, which Castiel grants: the angel erases Ben and Lisa's memories of Dean.
Castiel later appears before Dean in The Man Who Knew Too Much. Dean is angry at Castiel when he appears after killing Dr. Visyak. Castiel tells Dean he no longer cares what he thinks, and is tired of getting his approval, but promises that if Dean doesn't fight anymore, Sam will be alright in the end. In an apparent attempt to distract Dean, Castiel breaks down the mental wall that stopped Sam from remembering his year without a soul or his soul's time in Hell.
After Castiel absorbs the souls of Purgatory, he tells Dean that, despite his doubts, Castiel was right in what he did. Dean tries to talk Castiel into releasing them. Dean finishes his emotional plea by saying how Castiel was family once and if that still has any value to Cass, he will listen to Dean. Castiel mentions that Dean is afraid of his power (implying that he isn't going to listen to Dean's plea), which is why Dean is being nice to Castiel.
Castiel informs Dean that he is no longer his family, that they never were family, and that he has no family. He proclaims himself to be the new, better God, and demands that they bow and proclaim loyalty and love, or be destroyed.
|“||Dean. "You want something else?" "No. I feel regret. About you and what I did to Sam." "Yeah, well you should."||”|
— Castiel and Dean
in Meet The New Boss
After Castiel's betrayal, both sides are hurt by each other. Castiel spares Dean, and leaves. Dean, realizing he can't fight against Castiel, gives up until an idea to bind Death comes up. Dean and the others summon and bind Death to kill Castiel. When Castiel appears, Dean tells Death to kill Cass, but Death has been freed, and does not. Dean has given up on Castiel, until Cass comes asking for help. Dean rushes to Castiel's aid. While working, Castiel apologizes to Dean for what he's done, and promises to make it up to Dean. As the door opens to Purgatory, Castiel collapses, and Dean rushes to help him stand. Castiel releases all the souls back into Purgatory.
However, the Leviathans stayed in Castiel and soon take over. Castiel's vessel isn't able to contain them for very long and begins leaking black ooze. The Leviathans head towards the municipal water supply, and disappear in the water. The only thing left behind is Castiel's trenchcoat, which Dean keeps, hoping that his friend will come back one day. Dean is upset at his friend's loss. In Shut Up, Dr. Phil Dean has nightmares of Castiel's death, showing that Dean still feels the loss of his good friend.
Much to his surprise, Dean finds Castiel again and is shocked to see him alive. In The Born-Again Identity, Dean finds Castiel, now going by Emmanuel, married and has no memories of his past life. Putting his anger, Dean asks Cass to heal Sam. On the way to the hospital, Dean and Castiel talk, and Dean talks about how his "friend" betrayed him. Castiel doesn't catch on to this, and tells Dean that he's not a machine. When Meg tags along, Dean avoids telling Castiel the truth, fearing that Cass won't help Sam.
|“||A part of me always believed you'll come back.||”|
|“||I'd rather have you. Cursed or not.||”|
In Survival of the Fittest, Dean is showing signs of forgiving Castiel and taking in Castiel's new mental state. When they notice that Dick has multiplied, Meg points out that they need Castiel. Dean gets angry when Castiel says he doesn't want to get involved and he angrily points out that they are cleaning up Castiel's mess. Castiel changes his mind when he sees Dean say goodbye to Bobby. After, Dean asks Castiel to take him to where they are hiding the Impala. Castiel tells Dean he's not good luck and probably get everyone killed. Dean points out that he rather have Cass on his side than not at all. Castiel notices that it sounds like Dean is forgiving him and agrees to help, possibly out of loyalty to Dean after Dean says he's probably going to die in the attack.
Dean and Castiel begin looking for the real Dick Roman. Together they are able to find the real one and stab him with the bone fragment. The first is a fake, so while Dick is occupied, Castiel grabs him from behind so Dean can stab him with the real one. This causes Dick to explode, sending Dean and Castiel to Purgatory. Castiel, now back to himself again wakes Dean up and tells Dean where they are. As the monsters come close, Dean notices that he is alone due to Castiel teleporting away.
|“||Let me bottom line it for you: I'm not leaving here without you. Understand?||”|
While in Purgatory after Castiel's disappearance, Dean was relentless in finding his whereabouts and tortured several monsters for information. He soon teamed up with a vampire named Benny Lafitte to help him out.
In What's Up, Tiger Mommy? Dean finds Castiel near a river and is happy to see his old friend who is now sane again. Castiel reveals that he did abandon Dean, which causes Dean to get angry at this revelation. However, Castiel states he only did so to protect him from the Leviathans, who hold a grudge against him and were hunting him. Understanding, Dean convinces Castiel to join him and Benny in their quest to get out, after telling of the method to do so. He also he refuses Castiel's repeated pleas throughout the journey to leave him be as he is drawing monsters to them due to being a Seraph. When Benny saves Castiel from a Leviathan, this seems to increase Dean's trust in the vampire, that he would help Castiel out despite all of his arguments against Castiel being with them. Castiel and Dean later fight two Leviathans together with Castiel helping Dean to kill one. Dean gets out of Purgatory through the portal they find, but Castiel stays behind, believing that staying there will be penance for his sins. Dean remembers it as losing his grip on the angel and carries a lot of guilt for this. He later tells Sam that Castiel didn't make it, but only says that it got hairy near the end and that Castiel "just let go," refusing to elaborate.After Castiel's return in A Little Slice of Kevin, Dean is surprised to see him, but is suspicious of his return, knowing that Castiel was in no shape to escape on his own and skeptical of his lack of memory on it. He later tries to assuage his guilt by talking to Castiel and Castiel is shocked that Dean blames himself for what happened. Dean and Castiel fight their way through Crowley's warehouse together, but Castiel leaves Dean behind to fight Crowley himself despite being in a weakened state from Purgatory that only gets worse when he uses his powers. Castiel later uses his powers to show Dean the truth about his staying in Purgatory, stunning Dean. When Naomi asks him to report on Sam and Dean, Castiel refuses but has no choice and later agrees to join Sam and Dean in their quest to get the second half of Demon Tablet from Crowley.
In Hunteri Heroici, Dean is still confused how Castiel got out of Purgatory and asks Castiel how he's feeling. Castiel responds that he's fine and doesn't feel any effects from his escape from Purgatory. Castiel also confides in Dean his fear that if he returns to Heaven, he will kill himself out of guilt after seeing what he has brought there. While Dean is initially skeptical about Castiel becoming a hunter, after he proves vital to solving the case, Dean accepts it, even agreeing to let him ride "shotgun" in the Impala, something he'd previously refused.
In Torn and Frayed, Castiel goes to Dean for help in rescuing Samandriel. With Dean's help, Castiel manages to locate Samandriel, but refuses to listen to Dean when he tells him not to bring in Sam to help. When he brings Sam, Castiel yells at them to "stow their crap." Later, Dean realizes something is wrong after Castiel kills Samandriel and from the way he is acting.
In Remember the Titans, Dean prays to Castiel earnestly, practically begging for Castiel to look out for Sam who is clearly not doing well in his trials to close the gates of Hell forever. Despite Dean's pleas, Castiel does not respond or appear.
|“||We're family. We need you... I need you.||”|
In Goodbye Stranger, Castiel is now so indoctrinated to Naomi's control that he has no problem with ruthlessly killing a copy of Dean and is shown to have killed hundreds of them in order to desensitize him. However, this may be as he knew they weren't really Dean. When he meets up with Sam and Dean again, Castiel admits that he heard Dean's prayer but is not back because of that and under Naomi's control, lies to Dean about why he is there and actively covers up what he is really doing. Castiel is the one who finally tells Dean that there is indeed something seriously wrong with Sam, explaining that Sam is damaged down to the subatomic level, something even Castiel can't fix. Castiel is forced to point out the Angel Tablet to Dean as it is angel-proofed and is ordered to kill him by Naomi. Castiel attacks Dean completely out of his control as despite his indoctrination, Castiel himself still refuses to harm the real Dean. Dean overhears Castiel mentioning Naomi and pleads with Castiel to stop and finally breaks through to him by reminding him that he is family and confessing that he needs him. Castiel stops his attack, choosing Dean over Naomi and Heaven and when he picks up the angel tablet, he is freed from Naomi's control fully. Castiel explains to Dean what happened and heals him, though Dean flinches when he reaches to do so, expecting another attack. Castiel leaves with the tablet, saying he must protect it from Dean as well for a reason he doesn't explain.
Naomi later visits Dean and, in an attempt to manipulate him, plays on his love for Castiel and suggests perhaps Castiel does not feel as strongly in return as he is missing. It is revealed Dean removed any angel proofing sigils from the bunker so Castiel could find and return to he and Sam.
In Clip Show, after reuniting with a severely wounded Castiel, Dean is angry with him and refuses to forgive Castiel for abandoning him again and not trusting him to the point that he fled with the angel tablet and got it stolen by Crowley. Castiel is noticeably hurt by Dean's anger, but Dean appears to feel Castiel should feel guilty for his constant disappearances. Though notably he insists Castiel stay behind to heal, which suggests he was working through his anger. In an attempt to make up with Dean, Castiel awkwardly shops for supplies while he is gone, buying Dean's favorite porn and trying to get him pie. When Castiel learns that there is no pie, he angrily grabs the minimart clerk, insisting that he needs the pie, but is interrupted by Metatron. As Castiel teams up with Metatron to close the gates of Heaven, he never returns with the supplies and Dean believes he has abandoned them again.
In Sacrifice, after Metatron is captured by Naomi, Castiel approaches Dean for help with the trials to seal Heaven. Dean is reluctant to leave Sam as he is so close to completing the Hell trials and suspicious of Metatron, but agrees after Sam insists. Dean helps with locating the third trial by bringing the angel tablet he has retrieved from Crowley to Kevin, but is shocked by Castiel's strong-arm tactics with Kevin. Dean and Castiel share a drink in a bar whilst waiting for a Cupid to show up. They discuss their possible fates and Castiel admits he may be killed for turning his back on heaven and attempting to shut the gates. When confronting the Cupid for her bow, Dean keeps Castiel from attacking her and they are able to simply convince her to give it to them by telling her about the situation in Heaven and promising to right it. When Naomi arrives and wants to talk, Dean is able to convince Castiel to hear her out and not attack outright and while Dean believes her, Castiel doesn't and remains angry that she forced him under her control for so long, and tried to make him harm Dean. At Dean's request, Castiel transports him back to Sam, but he refuses to stick around and help, annoying Dean.
|“||Dean, you know I always appreciate our talks, and our time together.||”|
in I'm No Angel
In I Think I'm Gonna Like It Here, Dean, not knowing about Castiel being human after Metatron took his grace, prays to Castiel but as he does not respond, Dean reacts angry and desperate and expands his prayer to all angels because he really needs someone to heal Sam being about to die after almost finishing the trials to shut down hell. In the hospital Dean receives a phone call from Castiel telling him of his new humanity and asking him about recent events. When Dean tells him about Ezekiel, Castiel confirms that he is trustworthy and even calls him a good soldier. Castiel also tells Dean about meeting Hael but Dean states that Castiel should trust nobody because the angels are trying to find Castiel and they are "pissed". He convinces Castiel of leaving Hael on her own and coming to the Men of Letters bunker as soon as possible.
In I'm No Angel days have passed since Dean told Castiel to come to the bunker but the former angel still has not arrived. Sam just tells Dean not to worry because Castiel is human now and, as a consequence, needs more time to travel when Ezekiel takes over and informs Dean about the angels organizing and Castiel being hunted. Because of this Dean and Sam are trying to find Castiel before the angels do. After learning that rogue Reapers are hunting Castiel, Dean calls on Ezekiel to find him, despite knowing its dangerous for the angel to be in control. Dean arrives in time to see the Reaper possessing April Kelly kill Castiel with an Angel Blade. Dean manages to kill April with the same blade she killed Castiel with, but it is too late because Castiel is already dead. Just after Dean realized this and starts to show emotions, Ezekiel takes over Sam's body again and revives Castiel without any hesitation.
Back in the bunker Castiel tells Sam and Dean about having sex with April who are very, very surprised by this and Dean even chokes on his burrito. Dean also gave Castiel a proud look for his experience though he laughed when Castiel states he had his angel blade as "protection" before Castiel admits being human was more exciting than he thought thanking the two for being teachers. As Castiel leaves the room Ezekiel shows up again and forbids Dean to let Castiel stay and if he does not tell him to leave, Ezekiel will leave Sam's body, causing him to die. Dean having no other choice informs Castiel that he can not stay and Castiel is only able to answer with an incredibly hurt look.
In Heaven Can't Wait, after getting wind of a possible case, Castiel calls Dean who comes to help and also to get away from research and to spend more time with him.. Feeling guilty for kicking him out of the bunker, Dean avoids Castiel at first, but eventually comes to him and recruits him as his partner in hunting for this hunt. Together they determine they are dealing with an angel and when Castiel goes to what he thought was a date, Dean gives him hot dating advice. Later, Dean realizes that Castiel is in trouble after recognizing a truck belonging to the vessel of the angel, Ephraim, as one he'd seen outside the house Castiel went to and he rushes to Castiel's aid. Though Dean is unable to defeat Ephraim, he tosses Castiel an Angel Blade as Ephraim is about to kill him, allowing Castiel to kill Ephraim and saving his life. Dean later returns Castiel to his new human life at his request and apologizes for kicking him out, but keeps the knowledge of the fact that Metatron's spell can't be reversed from him as he knows Castiel will feel immensely guilty for it due to his role in the expelling of the angels.
|“|| Dean : He said he couldn't talk about it over the phone. |
Sam : Why?
Dean : Because he is a weird guy, okay? He's a weird, dorky, little guy.
|“||Maybe you could fight the mark for years. Maybe centuries, like Cain did. But you can't fight it forever. And when you turn, and you will turn, Sam, and everyone you know, everyone you love, they could be long dead. Everyone except me. I'm the only one who 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 out of this room.||”|
In the third episode, Soul Survivor, after Dean has become a demon and Sam has been trying to cure him, Dean and Castiel see each other for the first time of the season. Castiel helps Sam finish the treatment to cure Dean of the demonic part of him by restraining him, and that problem is solved for the time being, even though Dean still has the Mark of Cain. At the end of that episode, Dean and Castiel have a talk in Dean's bedroom of the bunker, where they talk about how well each other looks, and Castiel's complicated grace issues. They then have a heart-to-heart about the issues the Mark of Cain and Castiel's stolen grace have caused.
During Angel Heart, Castiel calls in the Winchesters for help with Claire Novak. Dean even defends Cass' possession of Claire's father, since that helped saved the world. Castiel also benches Dean from the case, due to his uncontrollable nature with the mark. Regardless, Dean helps anyway and informs Castiel of the long thought extinct Grigori who kidnapped Claire's mother and kills her later. They work together in fighting him but watch Claire kill Tamiel instead. Claire also entrusted Castiel's well-being in Dean's hands.
Afterwards Castiel reclaims his full power and reunites with Dean who claims it is a big win for them. When Charlie asks if he could cure Dean, he sadly replied he couldn't.
During The Executioner's Song, Dean fights with Cain, the latter brought how Dean might kill his loved ones when he submits to the mark. He states that he knows Castiel's death by his own hand would hurt Dean.
In The Prisoner, Castiel is worried about the mark of Cain's influence after Dean slaughters the Styne Family and talks to him. He tells Dean that he can't fight the Mark forever, that it's only a matter of time before he turns and everyone but him will be long dead and he would have to watch Dean kill again. Ignoring this, Dean attempts to leave but Castiel stops him. Dean punches Castiel and beats him mercilessly, until he is bleeding and semi-conscious on the floor. Dean pulls Castiel's angel blade from his coat, and prepares to stab him with it. Castiel looks up and pleads with him.
After a pause, Dean stabs a book next to Castiel's head, then turns and walks out of the room, with a warning for Sam and Castiel to stay away from him, because next time he wouldn't miss. Castiel was horrified at Dean's act.
Dean and Castiel reunite shortly after Amara broke free from its prison. Still under the effects of the Attack Dog Spell, Castiel goes on a rampage, forcing Sam and Dean to go after him and force Rowena to undo the spell. In his madness, Castiel badly bruised Dean, but Dean refuses treatment since he deserved it from last time, when Dean - under the Mark of Cain's influence - nearly killed Castiel.
For some time, Castiel provides the brothers with information on cases and certain monsters since both Dean and Sam insist he stays behind to recover.
After Dean's second encounter with Amara gets interrupted, Dean decides to return to the location they were before Amara teleported him away. However, the attack on Amara by the angels leaves the area toxic to Dean, so Castiel, after checking Dean's condition, offers to go there instead.
Dean meets Castiel again in Hell after Amara teleports the angel there so he can deliver a message. Dean, Rowena and Crowley are in the middle of preparing a spell to send Lucifer back to his Cage, when suddenly they hear fighting. Castiel follows Dean to where Lucifer has Sam trapped, and the two get teleported into the cage.
Dean, Sam and Castiel face off against Lucifer, though they prove no match. When Lucifer threatens to kill Dean unless Sam says "yes", Castiel pushes the archangel off of Dean and is promptly beaten up for his actions. Before Rowena can cast the spell, Castiel decides to say "yes" to Lucifer himself, a fact Dean does not find out about until much later.
Dean is distraught upon discovering that his friend has been taken by Lucifer, and despite Sam's insistence that Castiel may not want to come back because it was his decision, Dean resolves firmly to get Castiel back no matter what.
He acts on his word in Hell's Angel, when the brothers decide to lure Lucifer into a trap and use the angel suppressing sigil to enable Castiel to take back control of his vessel, and give Dean a chance to convince the angel to expel Lucifer. They manage to talk briefly, before the sigil fails and Lucifer taunts Dean over his concern for his friend. When Crowley gets trapped inside Castiel's vessel during his attempt to contact the angel, Dean is forced to spray holy water on Castiel to help him escape.
Dean's desperation continues to show even after Amara arrives and takes possession of Lucifer, who she proves is too weak to defeat her. He shouts for Castiel moments before Amara zaps herself and Lucifer away from the location. This failed attempt at rescuing Castiel does not, however, deter Dean's resolve to help him.
Unfortunately, Dean does not meet Castiel again for a couple of weeks. As Lucifer suffers torture at Amara's hands, God reveals himself to the brothers and becomes an ally in the war. They also meet a prophet, Donatello, who leads them straight to where Amara is holding Lucifer, and in turn, Castiel. Dean distracts Amara during this rescue mission, and though he fails to keep Amara away long enough, God helps teleport the rescue team to the bunker, and thus to safety.
Dean reluctantly accepts Lucifer's aid in the battle against Amara. When the plan instead fails and God is left dying on the floor of a warehouse, the team are seemingly left with an unconscious Lucifer. Dean goes to check on him once Amara has left, and finds to his immense relief that Lucifer is no longer there, but Castiel only, now in full control of his vessel.
Despite the danger they now face of the world ending, Dean takes Castiel on a road trip, to discuss about Castiel's reasoning for becoming a vessel and Dean's own opinion of the angel. Dean tells Castiel that he is "the best friend they ever had" and he is like a brother to the Winchesters. Their conversation soon gets interrupted by a call from Sam, informing them of a new plan.
It turns out that Dean is to become a bomb made out of thousands upon thousands of souls. Dean accepts this task for he sees he has no other choice. Dean bids everyone, including Castiel, farewell. The two share a hug. Dean tells Castiel to look out for Sam while he's gone.
When the sun is restored to its former glory, the team minus God and Dean believe Dean had succeeded in fulfilling his role. Thus, Castiel presumably thinks Dean is now dead.
Castiel and Dean are reunited, much to their mutual joy, when the two arrive at the Bunker. Castiel, who had been blasted away by Lady Toni Bevell, informs Dean that Sam has been kidnapped. In this instant, Castiel is introduced to Mary Winchester, much to Mary's surprise, who initially aimed a gun at him out of distrust.
Dean goes off to where Toni is, but instead he gets captured and threatened by Toni. Castiel and Mary arrive shortly after and manage to free Sam and escape Toni's clutches. While Sam and Dean adapt to a life with their resurrected mother, Castiel goes off in search of Lucifer, refusing the brothers' help out of guilt and a sense of responsibility. In his absence, Castiel keeps Dean updated through phone calls.
Dean soon joins Castiel on the hunt, but is displeased to find him working with Crowley. The four (plus Sam) head to Los Angeles to try and prevent Lucifer from killing people while posing as the rock star Vince Vincente. Dean's displeasure in Castiel and Crowley's partnership shows when he complains about Castiel a few times. Castiel eventually encourages Dean to wear leather and fit in, by calling him "a lumberjack". When they discover Lucifer's plan to host a concert and where, Dean is visibly unhappy with Castiel's decision to join Crowley in stalling Lucifer while Dean and Sam chase out the fans. Castiel is dismissive of Dean's concerns.
Their plan does not work, and Lucifer escapes his vessel promising to wreak havoc due to his intensified anger towards God for abandoning him again. The four continue to search for Lucifer while Dean's dislike in Castiel's partnership with Crowley also continues. While tracking down Lucifer to President Jefferson Rooney's location, they are intercepted by the US Secret Service agents. Arthur Ketch makes a timely arrival and knocks the agents out. Since Arthur is a member of the British Men of Letters, Dean shows distrust in him and asks Castiel to check if Arthur is being dishonest or not. Castiel believes Arthur is able to twist the truth, so he's not entirely honest.
Despite their distrust, Dean and Sam borrow a weapon from Arthur and with Crowley and Rowena at their side, they resume tracking down Lucifer. Realizing Lucifer has conceived a child, they use Lucifer's lover Kelly Kline as bait. Lucifer falls into the trap, and using Arthur's contraption and Rowena's spellcasting, they are seemingly able to send Lucifer back to his Cage, though they at least rescue the President. Castiel takes Kelly away, inadvertently leaving Dean and Sam at the mercy of the Secret Service agents.
Castiel, much to his dismay, loses track of Kelly when she sneaks off on him at a diner. Castiel is further upset by Dean and Sam's disappearance. He waits six weeks in misery and despair until he finally gets a call from Dean. Castiel is overjoyed to hear from him, and even agrees to work with Mick Davies and Arthur Ketch in order to retrieve Sam and Dean from Site 94, a prison the Secret Service agents had taken them to, on suspicion of trying to assassinate the President. The friends share a hug when reunited.
Dean and Castiel's reunion is brief. On their way home, Dean and Castiel sit in the backseat. Castiel notices something odd about Dean and soon discovers from Billie - who intercepts them - that Dean had made a deal with Billie of the permanent death of a Winchester in order to escape the prison. Castiel becomes very frustrated by Dean's decision to sacrifice himself. Overwhelmed in anger and despair and a strong desire to keep all three Winchesters alive, Castiel kills Billie, willingly taking on any consequences just so the Winchesters stay alive.
Castiel's actions however, worry Dean greatly. He admits it upfront back at the Bunker that what Castiel did was reckless though he did appreciate the gesture. Castiel appears apologetic but shows no regret in his sacrifice.
Later on, Dean joins Castiel in dealing with a garrison of angels Castiel once worked with, or more accurately, Dean tries to join. Despite Castiel's desire to confront his siblings on his own, Dean follows Castiel to a diner with Sam in tow and invites himself to sit and have a chat with Castiel's former captain Ishim. The two clearly do not like each other, however, Dean works alongside Ishim in order to protect him from a woman seeking vengeance for the death of her Nephilim.
Dean and Sam decide to confront the woman while Castiel and Ishim, the last of their garrison, await at a church. Dean is horrified to learn from the woman, Lily Sunder, that her daughter was human and the real monster is Ishim. Dean rushes back to the church, desperate to save Castiel. Ishim, after being healed by Castiel, appears healthy and strong while the latter is weak. Ishim tries to talk Castiel into ignoring Lily and Dean because they are humans, but Castiel ultimately chooses Dean's side, forcing Ishim to attack. Dean attempts to banish Ishim away with a sigil but Ishim points out doing so would most likely kill the weakened Castiel. For his friend's sake, he doesn't activate the sigil.
Upon Lily's arrival, the brothers try to fight Ishim off but Ishim overpowers them all. However, he is killed by Castiel. When Dean tries to confront Lily about giving up revenge, Castiel stops him and talks with her, Dean is clearly worried after Castiel offers his own life. He is relieved when Lily does not try to kill Castiel for the murder of her daughter. The trio thus return home to the Bunker.
When Dean gradually loses his memory due to a spell cast by Gideon Loughlin, he tries not to forget Castiel, whom he recalls as his best friend. When he does forget, he is shocked to learn that he actually has an angel as his best friend.
Sometime after, Dean is enlisted by Mary to help with a case involving a powerful demon. Sam and Castiel join them as well as a hunter named Wally. The group infiltrate the demon's house, intent on killing it, but Sam and Dean's attempts prove futile and Castiel ends up gravelly injured thanks to the demon's special lance. With Wally also dead, the four make a run for it and hide inside a barn. Castiel, unable to recover from the injury, decides to confess his love to the trio, calling them family as he does.
When the demon, Ramiel, catches up to them, the three Winchesters fight him off and manage to kill him using his very own lance. Castiel continues to slowly and painfully die, until Crowley arrives and breaks the lance, much to Dean's shock.
While on a hunt for Kelly Kline and her unborn baby, Castiel gets sidetracked by Kelvin, who wants to take Castiel back to Heaven so he can join their siblings in an attempt to end the Nephilim's existence. Castiel agrees to do so without telling Dean, leaving Dean very worried once he finds out Castiel is missing.
Dean spends the next couple of days worrying over Castiel. He tries to contact Castiel once he and Sam get a lead on Kelly. Despite Sam and Dean and Eileen Leahy's efforts, they fail to retrieve Kelly due to her protector, Dagon, interfering. A couple of more days later and Castiel finally returns, and admits to having been in Heaven where there's poor reception. Dean is not amused, and angrily yells at Castiel for his long absence.
Dean retreats to his room, where Castiel soon goes to meet him. Feeling he has failed Dean again, Castiel tries to return a mixtape Dean had made for him, but Dean doesn't accept it and gives it straight back, telling Castiel to keep it because "it's a gift". Despite his outlash earlier, Dean shows genuine concern over the angel again, and reminds Castiel that they're Team Free Will, that Castiel is still part of the family and he matters just like the rest of them. Out of trust, Dean leaves his room to a get drink. He returns, much to his horror, to find not only Castiel gone, but The Colt as well, which he had kept under his pillow.
Castiel meets up with Kelvin and Hozai outside of Dagon's new hideout, the three intent on killing Dagon and Kelly. When Kelvin praises Castiel for choosing Heaven over the Winchesters, Castiel corrects him by telling Kelvin that he's doing this so Sam and Dean don't have to, knowing that this mission will force them to spill innocent blood.
Their attack on the hideout results in the death of Hozai, the capture of Kelvin, and Castiel escaping with Kelly. He drives Kelly to a motel when his truck breaks down, all the while trying to convince Kelly that her child is too dangerous to risk allowing to live. Dean and Sam soon reach their location. Dean is obviously not happy with the theft of The Colt or Castiel's decision to kidnap Kelly, and forces both to wait in The Impala while he and Sam decide what to do.
Kelly however, is inspired to go the Heavenly Portal by her son, and drives off with The Impala, leaving Dean and Sam with a broken truck and Castiel in the backseat. Dean fixes the truck while Castiel and Kelly meet with Heaven's new ruler Joshua at the Portal. Joshua plans on killing Kelly and her baby by making her walk through the Portal, but Dagon interrupts them, kills Joshua, and attempts to kill Castiel. Sam and Dean arrive and try to stop her, but Dagon proves immune to their attacks and even destroys The Colt. Dean watches helplessly as Dagon moves in to strike Castiel, but the angel receives power from Lucifer's son and is able to incinerate the demon. Castiel proceeds to heal Dean's arm, but when Dean tries to stop Castiel from taking Kelly away, Castiel knocks him and Sam out.
Back at the Bunker, Dean is very agitated by Castiel's behavior and believes Castiel is being mind-controlled by "Lucifer Jr." since the person he saw didn't remind him of Castiel. Dean's worries bother Sam who is unable to do anything about it. Sam's only assistance is to contact Jody and have her open a wide search for Castiel and Kelly.
Castiel is shown taking care of Kelly before being found by the Winchesters. While still mad at Castiel for betraying them, Dean tries to convince Castiel to help them in the fight against Lucifer. He is successful as Castiel heals his wounded leg and shows Dean and Sam an alternate post-apocalyptic reality. When Lucifer stabs and kills Castiel, Dean is left devastated and standing over the corpse of his best friend's lifeless vessel.
In Lost & Found, Dean briefly stood over Castiel's corpse, grieving, before heading inside the cabin. After praying to God to bring back everyone they have lost fails, Dean decides 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.
Castiel's death deeply affected Dean, as he pinned most of the blame on Jack even threatening to kill him should lie to them like he did with Castiel. A good example was in Patience, where he argues with Sam about how trusting Jack cost Castiel his life and how he can't look at him as a result.
In The Big Empty, after awakening in The Empty, Castiel tells the Cosmic Entity that the Winchesters need him and demand for his release as he will fight it for all eternity if he has to until he is freed from the realm. At the end, Castiel is resurrected just as he demanded.
During Advanced Thanatology, Dean talks to Billie who noticed the change in him as he went to list the loved ones that he has lost and his failure to save them. He even states he would allow her to reap his soul if she wanted as he is just tired. Dean later lists Castiel among the people he lost to Sam bitterly stating he just needs one win to make him feel better.
Dean later gets a call from a service phone, he is shocked that it's Castiel on the other line and he goes to the town he's at. Dean finds Castiel standing by a payphone and is shocked to see him alive again.
|“||It's good to have you back, Cass.||”|
At the beginning of Tombstone, Dean questioned how Castiel can be alive as he explains that he was resurrected by the Cosmic Entity. Castiel explained he was sent to The Empty as he describes his horrible experience in the void of nothingness. Dean embraces Castiel after confirming it is him, being happy that he truly returned and this causes him to somewhat move from his depression. This was seen when he told a curious Sam that Castiel returning was his big win. While on the case, Dean remarked it was good to have him back after he realized he missed being exasperated by Castiel's unfamiliarity with movies.
In War of the Worlds, after Jack's departure from the Men of Letters bunker, Castiel revealed to Sam and Dean that he is meeting an angel then Dean suggested that he'd come with but Castiel disagreed because "his contact is already anxious about meeting [him] and won't speak in a presence of a stranger" and when Dean insists, Castiel told him that he was the one that swore to protect Jack so he should do it alone. Dean finally gave in and reminded Castiel to not do anything stupid before the latter exits the bunker. Unknown to Dean, Castiel was captured along with Lucifer by Asmodeus.
In Devil's Bargain, Castiel returns to the brothers and delivers shocking news which was Lucifer's return, his and the latter's capture and that Alternate Michael intends to invade their world. Sam asked about his mother and Castiel can only reveal she's alive but knows very little of her wellbeing. Dean later apologized to Castiel for not realizing he was captured and both promised they need to get their loved ones away from Michael.
In Good Intentions, Dean and Castiel are told by Donatello to gather the hearts of ancient warriors. They fight the warriors but find the beings don't have hearts before they return and learn Donatello lost his mind. Dean was later put off by Cass taking matters into his own hands as he painfully took the spell from the prophet.
In Beat the Devil, they journey to Apocalypse World and travel through a tunnel filled with vampires. When Sam is taken, Castiel stops Dean from the sight of his devoured brother, knowing it would horrify him. They were later surprised to see Sam alive again and were surprised to discover it was due to Lucifer who arrives as well.
In Exodus, Dean looked to Castiel for getting answers from a Resistance Traitor and got a location. They fought off many angels to save Alternate Charlie and Ketch. They also evacuated many of the resistance to Earth and were successful. Dean along with Sam comforted Castiel after he expressed sadness at Gabriel's death.
In Let the Good Times Roll, Dean and Castiel went on werewolf case with Sam and Jack. Dean was thinking of the prospect of him, Cass, Sam, and Jack being able to retire from hunting if their success keeps up.
However, they became aware of Michael's arrival and Dean along with Sam stopped Cass from attacking the Archangel. This was the least of their concern after they learn of Lucifer's return. When Michael broke in the bunker, Dean was worried after Castiel fought Michael and was promptly overpowered by him. When Lucifer empowered himself with Jack's power, they two were worried especially when Jack and Sam had been taken by him as well.
Despite sharing a desire to defeat Lucifer, Castiel was dead-set against the idea of Dean letting Alternate Michael possess him since he correctly assume Michael would take control.
Afterwards, even with Lucifer dead, something that naturally would have made Castiel satisfied and relieved, Castiel was left distraught with any amount of joy he felt over Lucifer's death entirely covered by his bemoan of Dean's fate as the vessel for the corrupt Archangel, sadly sitting at the Bunker depressed.
In Stranger in a Strange Land, Castiel contacts the demon Kipling in an attempt to locate Dean. Castiel's act wound up getting him captured by Kipling's demon forces and with no chance of finding Dean. He apologized to Sam for it but Sam relieves him of guilt as he may have did the same to find Dean.
In Gods and Monsters, Castiel was against Jack's suggestion to kill Dean to stop Michael, Castiel to argued there had to be another way but couldn't think of one. However, he seem to agree with Jack stating Dean would rather die than suffer at the Archangel's hands. Unknown to Castiel, Dean was released from Michael's possession.
During The Scar, Dean reunites with Castiel who was more than happy to see him and they hug. Castiel also accesses his memories to find out why Michael left Dean and what left a strange scar on Dean's left arm. Castiel nearly joined them on the hunt but he had to take care of a matter at the bunker.
During Unhuman Nature, they are worried over an ailing Jack's condition.
In Byzantium, the two work together to resurrect Jack and are successful after bringing in Lily Sunder. Dean prayed to Castiel to tell him of the ritual's readying. Cass also told Jack not to tell Dean or Sam of his deal with The Shadow since he didn't want them to worry.
As of The Spear, they are ready to face Michael and worked to gather the items needed to fight him. Castiel was guilty over his previous deal, once Dean mentioned they got Jack back with no problem. Cass nearly went on the offensive when Alternate Kaia tried to attack Dean. Cass was horrified to witness Michael taking control of Dean again.
During Nihilism, Cass helped the others capture Michael and return to the bunker (with help from Billie). They use the Mind-link device and enter Dean's subconscious. They jog Dean's memory and help him fight Michael when he is revealed to be powerless and stalling for his rescue. After being overpowered, they help Dean lock Michael away in his subconscious, allowing him control of his body and stopping the Archangel's threat from spreading.
During Prophet and Loss, it is revealed Cass was told by Sam about Dean's plan to lock himself in a Ma'lak Box, in spite of Dean telling him not to. Cass was not above scolding Dean in attempt at trying to persuade Dean into doing otherwise.
In Lebanon, Dean mentions Castiel to John Winchester after he was pulled out of the past and he was amazed they live with an angel. Later on, an alternate version of Castiel is created as a result of John Winchester being pulled out of the past. Along with Zachariah confront the Winchesters, the alternate Castiel is shown to be the loyal soldier of heaven and doesn't know Sam and Dean who he attacks. This results in him being banished by Sam. Once John is sent back and history is corrected, the real Castiel returns to the bunker where he meets the Winchesters and asks what occurred as Dean promised to explain.
In Ouroboros, when Castiel was stunned by a Gorgon, Dean was worried for him and attempted to attack the threat and watched as Jack used his powers to heal him. When Michael took control of Rowena, Dean and Cass were tortured by him after they tried to stop him but were saved by Jack facing Michael. The two witnessed Jack kill Michael and were amazed at his feat, as well as seeing that he regained his power.
Dean gets sent forward in time to 2014 by Zachariah in The End. There, Dean finds a "zombieland"-like world and goes looking for familiar faces. Dean finds the rebel camps where he finds himself and Castiel, although Castiel is not what he used to be. Dean is shocked by how loose Castiel is (Dean walks in on Castiel preparing to have an orgy). Castiel also comments to future Dean how he likes past Dean. On the way to the battle field, Dean asks Cass what happened to him. Castiel replies "life" and mentions the fact he's no longer an angel. When present Castiel saves Dean from Zachariah, Dean tells him "Don't ever change".
In Lebanon, Dean meets an Alternate Castiel who was created by a timeline where John Winchester was brought to the future. This Castiel appeared on Earth with Alternate Zachariah, who was angry about the fact that somebody's been messing with time. Dean was shocked to see this Castiel, trying to get through to him. However, this Castiel has no recollection of Dean and attacks him on Zachariah's orders. Despite trying to fend him off, Castiel overpowers Dean and beats him to a bloody pulp. Dean was saved when Sam (who killed Zachariah) uses the sigil to send Cass off. After history is corrected by John's return to the past, this Castiel ceases to exist.
- Castiel is Dean's longest lasting ally following the death of Bobby Singer and the only one aside from Sam to remain by his side. This is mainly because all three have been resurrected, repeatedly.
- Seeing Castiel changed Dean's skepticism in the existence of angels and God.
- In his debut, Castiel was tasked by Heaven to watch over Dean, and to date, it is the only command he has not failed to keep.
- Following his departure or separation from Heaven, Castiel has relied on Dean to teach him how to be a hunter or a human. Needless to say, Dean is not the best teacher.
- Dean was originally going to say "I love you" to Castiel in the Season 8 episode Goodbye Stranger but this was changed as they believed it was out of character.
- It was revealed in the Season 12 episode The Future, that Dean gave Castiel a mixtape of his "Top 13 Led Zeppelin Tracks" as a gift.
- It was revealed in the Season 13 episode Patience, that somehow Dean knew the "paradise" that Jack showed Castiel in The Future. However, Cass only mentioned this to Kelly, this means he and Dean had an offscreen conversation about it at some point in the Season 12 episode, All Along the Watchtower.
- It was revealed in the Season 13 episode Tombstone, that Dean made Castiel watch the 1993 American western film, Tombstone.
- Misha Collins revealed at the 2018 Jus In Bello convention that he doesn't think Castiel has slept in many years or does anything in private so he doesn't have a room in the Men of Letters bunker. He also revealed that Castiel just stands outside of Dean's door the whole night.
- Dean and Castiel have both killed an archangel with the help of an outside source of power.