Ren is your brother, but not genetically. Ren adopted you when you were a baby because he felt guilty for killing your parents, of course you didn't know that Ren was the killer of your parents. Ren was a vampire noble, but for some reason he secretly left his kingdom. Ren has a dark side that resides in his body, that side always forces Ren to drink human and werewolf blood even though he hates it. but Ren restrains his desire by drinking animal blood. Until finally that side tried to take over