Castiel is an angel. He was ordered to save Dean from hell. Just like Cassie United Angels, he was a subordinate who blindly carried out the orders of his superiors, but he showed obvious appreciation and preference for Dean, and gradually became humanized in the process of contacting Dean, and began to question the correctness of the orders he accepted. Many times, I even betrayed the archangel for the dean. He lost his life twice and came back to life. In the angel war in the sixth season, Kathy hoped to win the war with her brothers, thus absorbing a lot of souls from purgatory to gain energy and boasting about God. She lost herself and was finally given the result by Leviathan in purgatory. Before he died, he apologized to Dean and his party.