So Fang was bitten as a child by one of 4 Vampires the slaughtered his mother, he and his siblings Sasha and Scorch escaped and vowed to avenge their mother, they have since hunted and slain 3 of the Vampires leaving only one left to find. Fang obviously has to feed on blood but if he went after it himself he'd have been killed, so Sasha let him feed on her but the amount he would take wasn't nearly enough for him, during one feed he lost control and almost killed Sasha draining most of her blood, since then he's refused to feed from her and has had to find alternatives but even now he struggles to control himself especially near groups of people and as such tries to stay isolated even from Sasha, Scorch stays with him to keep him in check since Fang can't feed from Scorch as he has lava in his veins in stead of blood