User blog comment:A.J AL/Season six plot hole./@comment-58.178.131.226-20121229130330

Castiel needed Crowley alive to look after Hell and more important keep Lucifer and Michael in their cage. If he had killed Crowley than I would think the demons would have likely wanted to release Lucifer again as a way of following a leader and knowing what to do. Don't hate just my opinion I'm glad we got too see Leviathans :D