The vampire first notices my characters' existence because my characters kills a vampire drug lord, who's one of his contenders. Then my characters come into conflict with him because they suspect that he kills people. There's just one thing that makes me hesitate: the side of mages that don't like change go after supernaturals, so it will be smart for him not to work with them and I guess it's not easy for a vampire to get the trust the other side of the mage due to folklore bad rep. My vampire will try to get an edge whatever he can, but I don't know what claims he can make to get the others to cooperate with him.