Until the age of twelve, Perseus Jackson was known as Percy Winchester. He was practically raised by Sam, Dean, and Bobby Singer. And, up until Dean's demon deal ran out, he was considered alive. The fateful night of Dean receiving the Mark of Cain is rudely interrupted, leading the Winchester brothers to find their brother, The Dark Hero, and the ones who have been pulling the strings since the very beginning. Not everyone is going to make it out alive. All characters belong to Rick Riordan and the writers of Supernatural