Hi! I havent read anything about this, so maybe its nuts but... What if Cas's soul is in hell? Cas was human once, so that means he had a soul, right? The angel part of him is gone, but his human part is either in heaven or hell. But, since Cas killed a reaper, I dont think anyone would want him in heaven. And since Hell doesnt have anyone on charge since both Lucifer and Crowley are gone, maybe Michael gets to leave the cage too. Maybe he is a part of getting Cas out of hell.