who brought castiel back to life in season 5
Castiel (Supernatural) Although Castiel is confirmed to be dead, Jack, Lucifer's son, who regards Castiel as his guardian, is able to make Castiel 'wake up' in the Empty, the place where angels and demons go when they die, and is eventually returned to life when the entity that controls the Empty finds him annoying now that he is the first being to awake in that place. However, he is subsequently captured along with Lucifer when Lucifer returns to this world to warn them about the Michael of the parallel universe, who seeks to rule this world as well.