Dean agrees to be new God Castiel's pet in return for the resurrection and safety of his family and friends. The fly in the ointment is that his training is turned over to the pagan goddess Despoine. Her family of gods are in the habit of farming human beings for their meat..
"Why does he make me care so much?" Castiel asked, looking at the pet in front of them. "He's aggravating, he judges everything I do, talks back no matter how often I tell him otherwise and thinks he knows better what's right or wrong than anyone else in the world."