Here's the idea at its core: he's essentially an immortal bon vivant. He literally created the condition of vampirism so that he could live luxuriously forever. He's a debaucherous hedonist, with horrifically sadistic tastes and pleasures. Like Dorian Gray turned up to eleven. The complexity of the character draws from his perspective from having lived for so long; the world is his playground, and he doesn't want anyone mucking it up. Anyone who would rule over or destroy the world is in direct opposition of his goals, and he finds himself compelled to stand against them. He doesn't really care about good or evil, or right or wrong. He just wants to get loaded and have a good time. That aside, he's also an exceptional swordsman and a powerful magician who specializes in a strange, arcane art known as "sangromancy."

EDIT: I do see your point, and I would agree that this sort of thing would become routine to him after so long. Perhaps we can reach a compromise here in some way, maybe just toning him down to be more or less the same character, only younger, and this is the first of his "chores."