Between Jensen Ackles and Misha Collins fanning the flames of the Dean/Castiel shippers since Supernatural ended, audiences continue to speculate what the relationship between the pair means. Between Latin American dubs confirming the romance and The CW playing coy, there are more questions than answers about one of the internet's most popular ships and its place in the show's canon.
They started on the wrong foot but with time, they grew to be best friends. With Ackles developing the prequel, some fans are hoping that this new series might give them something to salvage the ambiguous note that the series finale left on.
Season 4 - The First Meeting And The Rebellion
Many are aware of the fact that Castiel was originally written to be in a couple of episodes. However, the moment Dean and Castiel meet in that barn in the season 4 premiere, the chemistry between Jensen Ackles and Misha Collins is so off the charts that they decided to keep Castiel longer and the rest is history.
Castiel pulled Dean out of Hell and at first, they are at odds with each other. However, soon Castiel begins doubting everything he knew because of Dean, and at the end of the season, he rebels against Heaven for Dean.
Season 5 - Becoming Close Friends
After rebelling from heaven, Castiel starts hanging around with the Winchesters more because he believes in their cause. Sam and Dean had a bit of falling out in the last season and in this season, fans see the after-effects as the two go on their different ways for a while.
The result is that Dean spends more time with Castiel and they make a great team. Dean even admits that he is happy after a long time because of him. By the end of the season, they become extremely close friends.
Season 6 - The Blind Trust And The Betrayal
Supernatural had a little trouble finding its footing after Kripke's departure and season 6 had a lot going on. In the end, Castiel was made a villain and it turned out that he was lying to Dean and Sam the entire season.
The interesting thing is that when Sam and Bobby are suspecting Cas, Dean is showing blind trust towards the angel. This proves how close they had become that Dean trusted him blindly even when his every instinct said otherwise. When Cas' betrayal finally comes to light, their relationship gets distraught.
Season 7 - Time Apart
The beginning of season 7 saw Leviathans taking full control of Castiel and Dean sees Castiel explode in the lake, surmising that Cas is dead. Through the majority of the season, Dean's mental health keeps on declining and what happened with Cas is one of the primary reasons.
Cas comes back with his memories wiped and Dean hands him his trenchcoat, which he was carrying with him since he lost Cas. This is a testament to how much Cas means to Dean that even after all the lies and betrayal, he still couldn't let him go and hoped to see him again.
Season 8 - Purgatory And Mind Control
The end of season 7 leads Dean and Cas to Purgatory where they remain for a year. Dean, again showing loyalty to Cas, does everything in his power to get him out of there. When Cas doesn't come back out of his own will, Dean blames it on himself.
However, when Cas does return, he is in control of Naomi, who ultimately pushes him to kill Dean but Cas breaks away at the last moment. His bond with Dean proved to be stronger than an angel's mind-control.
Season 9 - Human Cas
Castiel becomes human in season 9 and it is an extremely difficult time for him but Dean couldn't help him because Sam's life was in danger. He kicks Castiel out onto the streets despite him not wanting to do so.
However, Dean comes back to check on him, and even though, Cas is somehow hurt by what Dean did to him, he still can't push him away completely. Fans get some cute moments between them when Dean drops Cas for his date and gives him some tips. At the end of the season, Cas again has to choose between heaven (this time an angel army) and Dean, and to no one's surprise, he chooses Dean.
Season 10 - Mark Of Cain
In season 10, Cas spends more time with Sam than with Dean. This should feel odd but it doesn't because Sam and Cas are working together to save Dean. In such scenes, fans can see that Cas cares about Dean as much as Sam does, if not more.
Whereas Cas is seeming more like a human than an angel, Dean is losing his human side to the Mark of Cain. By the end of the season, Dean beats Cas bloody under the effect of Mark of Cain when Cas tries to stop him but when it comes to killing Cas, he can't do it. This is a running theme for them because they can't seem to kill each other even when they are overtaken by curses or mind control.
Season 11 - Casifer
In an attempt to save the Winchesters and the world, Castiel yet again sacrifices himself. Castiel says yes to being possessed by Lucifer in the hope of Lucifer beating Amara. This does not go to plan obviously and so, Cas is hardly seen as himself in this season as he remains possessed by Lucifer, better known as 'Casifer' in the fandom.
This season showed how much Castiel wishes to be useful to Dean since he is no more the powerful angel that he used to be. He thinks that Dean will only want him around if he is useful, which is not true, but in that desperation, he can do anything.
Season 12 - Family And Death
After the events following season 11, Castiel is guilt-ridden and he makes amends for that by doing everything he can to save the Winchesters. Interestingly, the season starts with Castiel hugging Dean tightly upon seeing him alive and it ends with Dean screaming upon seeing Castiel being killed in front of him.
The season follows the theme of family and how Cas has integrated well into the Winchesters' clan even if he doesn't realize it. Dean shows time and time again this season how much he wants Cas to be alive and with him, even if Cas is not as powerful as he used to be.
Season 13 - Grief And Subsequent Reunion
Cas died in the season 12 finale and season 13 starts with Dean dealing with the grief of losing Cas. He has become completely hopeless and devastated, and he remains like that until Cas is revived.
The "Tombstone" episode shows how much Dean is happy to have Cas back and he even conveys that to Sam, calling it "a pretty damn big win". The episode dives deep into their relationship as they both dress up as cowboys and talk about watching movies together.
Season 14 - Fatherhood
As Jack officially becomes part of Team Free Will 2.0, season 14 of Supernatural sees the Winchester brothers and Castiel dealing with fatherhood. However, this isn't all good for Dean and Cas. Jack accidentally kills Mary and Dean blames Cas for that.
Their relationship becomes immensely strained. When Dean traps Jack in the Ma'lak Box, Cas stands up to him in defense of his son. Until the end of the season, Dean and Cas are at odds with each other due to Jack, especially when Dean tries to kill Jack.
Season 15 - Love Confession
The tension that started between Dean and Cas at the end of season 14 continues in the final season of the show. Dean refuses to talk to Cas even though they are fighting against God. They finally make amends when Cas' life is in danger in Purgatory and Dean reveals how much he is sorry for pushing Cas away and how much he needs him.
The season centers a lot around their relationship and it all comes to a culmination point when Cas makes the romantic declaration of love before sacrificing his life for Dean yet again. The entire speech is one of the most romantic confessions as Cas makes Dean realize that he is worthy of Cas' love.