The Chronicle Tale of Two Brothers, A Lion and A Snake

What do you do if you wake up inside a story, but it's not the version you've read before?. A boy dies and wakes up in a strange place only to realize it is one of his own fan-fictions. And unbeknownst to The wizarding world, Lily and James Potter had another child, Hadrian Potter. How will Harry react when he finds out that he has a long lost brother who turns out to be a vampire.