 At the end of the third season of "Supernatural", main character Dean Winchester is in Hell after being killed by the hellhounds of the demonic antagonist Lilith.In the season four premiere "Lazarus Rising", the angel Castiel is introduced as the one who brought Dean back from Hell and resurrected him.Because merely perceiving his actual form typically results in blindness, he takes a human host – James "Jimmy" Novak, a "devout man" who prayed for it – to communicate with Dean, and tells him that he has been brought back because God has work for him.