The Unseen

Season 4 AU (Sam and Dean aren't related). Aidoneus, more commonly known as Hades, was driven out of the underworld by demons and has been wandering the earth ever since. Along the way he fell for a mortal, and rather than lose him completely he bound their souls together. Two reincarnations later, Hades is going by Dean and roaming aimlessly around the states waiting for his bondmate, until one night he takes the seat next to Sam Winchester in a bar. Dean claims to be a hunter, and it’s all fun and games riding around in the impala and taking out ghosts until he suddenly finds himself wrapped up in stopping the demons’ plot to free Lucifer from Hell. They have to find a way to take down Lilith – even as Sam learns Dean’s true identity, and Dean discovers that Sam isn’t who he'd thought he was either.