Characterization
Castiel typically displays very little emotion and always exhibits an extremely somber disposition. Although it has been suggested angels possibly do not possess the ability to truly feel emotion, Castiel frequently exhibits affection towards Dean. This attachment and growing ability to feel even causes him to be "demoted", as his superiors fear emotions are clouding his judgment. Throughout his appearances in the fourth season, he also seems to, at the very least, come close to expressing regret, hesitance, and anger several times, and has once quietly laughed at a joke Dean made in "It's the Great Pumpkin, Sam Winchester". Actor Misha Collins feels, through Dean, " learning a little bit about humanity and re-learning something about own humanity from that exposure. So...there’s a humanizing of Castiel going on." Castiel begins having an internal struggle between what is right and what is wrong, and whether or not to obey orders from Heaven. Collins feels this is because interactions with Sam and Dean have made the angel "uncertain" and "more fragile". Collins believes Castiel envies Dean's decisiveness and desires to emulate him. Having lost his connection to Heaven in the fifth season, Castiel's humanization seems to have quickened by the episode "Free to Be You and Me", as he appears extremely anxious while in a whorehouse, is visibly distraught when asking Dean for help, and refers to the Archangel Raphael as "my little bitch". Despite becoming very arrogant when he becomes the "new God," Castiel still shows his caring side and ultimately returns the souls to Purgatory and shows remorse for his actions, promising to Dean to find a way to redeem himself in Dean's eyes, showing that he cares about how Dean views him. After losing his memory, Castiel is more human than ever, but still displays some of his emotionless side. After his memory returns, he shows real regret when he can't undo the damage he did to Sam and essentially sacrifices himself to save him out of remorse for his actions. After Castiel wakes up from his catatonic state, he is now depicted as insane with tendencies to ramble about random topics. However, parts of Castiel's original personality are still shown with him still being happy to help Sam and Dean out and still knowledgeable about various supernatural things, but not willing to actually fight anymore even when his life is threatened. Castiel describes himself as "bad luck" and doesn't believe he should be around the Winchesters as a result. After traveling to Purgatory, Castiel regained his sanity, but still carries a lot of guilt about his previous actions. He is also now less distant from Sam and Dean and more appreciative of human things such as television.
Contrary to depictions of angels in popular culture, Castiel and his peers are not out helping people in need. Contrary to his angel siblings he has a conscience and cares about humanity's welfare—he finds humans to be "works of art". Speaking of his character, actor Misha Collins stated, "I think that these angels are at least loosely derived from some Biblical angel stories, and those angels are . They just destroy. I picked up Revelations, and they destroy, they destroy, they destroy. There’s no mention of cherubs and harps or any of that."
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