The Angels, they don’t care. I think maybe they just don’t have the equipment to care. Seems like when they try, it just breaks them apart. - Dean Winchester, 7X21
Dean did not realize it here, but he would become: the cause by which Cas would direct his steps, the reason for Cas’ fall, and the love of Cas’ life. (4X21)
This was just after a Cas reprogramming. It had become clear to Heaven that Cas was being swayed by Dean. Oh, this scene just breaks my heart, how dead Cas looked in his eyes. This also reiterated that Cas had been serving/following Dean specifically. (4X20)
Dean was the reason that Cas rebelled, to the point Cas killed his own and was hunted. This speech from Cas was sobering, and a little while later we got blessed with “Free to be You and Me”, one of the most Destiel-heavy episodes. (5x02)
But then Dean was sent to the future and the illusion of happy-Destiel in 5x04 was shattered. It was there that Dean witnessed, with his own eyes, just how slippery the slope was if Cas continued to follow him. Cas’ only reason for staying at Camp Chitaqua was Dean. Cas didn’t agree with Dean’s plan, not one bit. But where Dean would go, Cas would follow.
And that’s what is meant by, “Me and him, it’s a pretty messed up situation we got going…” in which the camera pans over to focus on Cas. It was to emphasize that the only reason Cas was there was for FutureDean. Their relationship had become warped and unbalanced. Cas was willing to give everything, and FutureDean was willing to take it all because he was blinded with rage and revenge, and that didn’t sit well with our Dean at all. (5x04)
And it was why, when Dean returned to his own timeline, that he implored Cas to not change. What he meant was that he didn’t want Cas to become broken and addicted and suicidal for Dean’s cause. He didn’t want Cas to follow a corrupted Dean who would allow Cas to die for his own revenge. (5x04)
But the wheels were already set in motion. Cas was already changed, so Dean’s remark only served to further Cas’ resolve in following him and continue rebelling against heaven. And Cas’ cause, that he fully served, was Dean. The programming to make him otherwise just wouldn’t stick, no matter how many times the angels tried to change Cas back. (7x21)
Dean learned that it was when Cas first laid a hand on him, to rescue him from hell, when Cas first became lost. Cas was very unwell at this point. Dean believed that Cas was this broken angel because of him. (7x21)
Even though he saw that Cas was willing to follow him in Endverse, to death, Dean seemed surprised that Cas was still willing to follow him after all they’d gone through since season five. One would think that all of the betrayal, and catastrophe, and the fact that Cas was currently mentally unstable because of the Winchesters, would be enough for Cas to throw up his hands and say, “I’m done with you.” But no matter what happened, Cas would go… and he’d do his best. (7x23)
Purgatory was pure. It gave Dean clarity and this is when he knew, without doubt, that he needed Cas, come what may. He even told Cas this: “I need you”. And not just to fight battles, but because Dean finally had someone in his life who cared for him unconditionally, and that he cared for unconditionally right back. He wanted them to go home, together. (8x07)
Purgatory was also a time that Cas didn’t come when Dean called (”I prayed to you, Cas, every night.” “I know.” “You knew and you..?”). It was also a time when Cas chose to not follow Dean. And it hurt Dean. It hurt him so badly that Dean couldn’t comprehend it. His mind had to compensate for the rejection by creating an alternate scenario for why Cas stayed behind in Purgatory instead of going with him. Cas had stayed because he wanted to serve penance for the terrible things he’d done, things that he had claimed, “I ‘m doing this for you, Dean. I’m doing this because of you.” (quote from 6x20; gif from 8x07)
Heaven continued to be frustrated by Cas’ rebellion in regard to Dean, to the point that Cas was reprogrammed–yet again–and this time he was set to kill. Because they knew that Cas would defer to Dean before Cas listened to them. This is how much Cas served Dean. But even their programming wasn’t enough. Dean’s love confession broke through the mind control. Afterward, Cas would once again disappear and it would seem, to Dean, that Cas was back to serving Heaven (ugh, he wasn’t Dean). (8x17)
But if we fast forward through a lot more misunderstanding, Metatron confirmed that Cas had been under the guise of following Heaven, but all of his choices were for Dean. You know, in case it wasn’t clear enough already because viewers hadn’t been paying attention. (9x23)
Cas continued to lose his grace through season ten, and became possessed by Lucifer through most of season eleven. At the season eleven finale, Dean was on a kamikaze mission to annihilate Amara and Cas offered himself to Dean once again: where Dean would go, Cas would follow, even to death. But Dean finally put his foot down. He couldn’t be the reason Cas died, not like Endverse. Instead, Dean imparted a new cause for Cas to serve, and he asked Cas to watch over Sam. (11X23)
Cas was downright depressed and downtrodden in season twelve. He felt weak and useless. If he couldn’t serve Dean, then he felt Dean would no longer need him. And it was during this time that Dean was reminded, again, just how much Cas had changed, and all because of him. Yes, Cas has never fully done what he was told (Naomi said as much in 8x21), but Dean was the point of no return for Cas. (12x12)
During season twelve, Cas found another cause to serve: Jack. This role was different from his role and relationship with Dean. This would become a parental role. One of the greatest things to happen this season, though, was for the brothers to see what could have been had they not been born, in a sorta “It’s a Wonderful Life” twist. They got to see the world they never saved. (12x23)
So imagine my utter disappointment when we finally meet AUCas and he is quickly ended before Dean gets a chance to see: a Cas that he never saved.
Both Castiels were right: they are the same. They both didn’t do as they were told, and had to be reset by Heaven again and again. Both of them were different from their angel brethren. But they also differ because AUCas never found his Dean/humanity and so he became corrupted, broken, wingless, twitchy and evil. AUCas didn’t get away from Heaven or Heaven’s control.
Dean could have benefited from seeing AUCas:
to see what becomes of a Cas that is never changed by Dean/humanity
to realize that a changed Cas is not a broken, lost Cas
to let go of the guilt that the things that happen to Cas, as Cas lives his life, aren’t Dean’s fault just because they’re in each other’s lives
and to understand that the moment that Cas saved him from hell was also the moment that Dean, in turn, saved Cas
No, Cas wasn’t lost when he laid a hand on Dean in hell.
