two hundred years of war
Since Sam and Dean don't exist in au, Michael and Lucifer definitely skipped the true vessel bs then went to war with angels and demons in their true forms (angel blades sticking out of the ground proves it). That means au Cas is in his true form and Jimmy Novak is probably dead in a ditch somewhere. I hate the idea of Jack resurrecting Cas cause that'd be too easy and basically turns him into god. So when Misha comes back, how can they bring Cas back with him?