Supernatural

41 year's ago the Yellow eye demon, Azazel, tried to draft little Sam Winchester to an army known as “the children of Azazel”.
His plan didnt work as he thought.
Little Sam and his older brother Dean became two of the most legendary monster hunters.
Ascertained that, Azazel went back in time to kill Sam as a baby and erase his existence permanently.

You as a figurative team of hunters receive a message from boys loyal friend
Bobby Singer:
“ The boys are in pergatory. I need help to stop him. I've been informed he didn't come back alone.”