Let me see, apart from myself I would say Marcus from Underworld, he was one of the first vampires and his hate for what the others became and a mutation with werewolf blood furthered his powers giving him the ability to change. It was cool how he apeared to be just standing there and then sudenly you see that he stabs the person with his wings.
I know a lot of vampires but thinking of powerful is different from just cool, but I havent actualy seen Helsing. Though often the half vampies are strong in things.
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Through dream I travel, at lantern's call
To consume the flames of a kingdom's fall