Angel
It would only be more complicated if you were brothers.
Vampires live in secret, generally, but there are towns and places where knowledge of them is more common among the upper crust of society. I came into the social sphere of vampires without being aware of it, originally. Most vampires cannot go out in sunlight, so there were clues. One who had grown fond of me, who had introduced me to the others, told me that he had betrayed me from the beginning. One of them, one of the strongest vampires in the whole world, wanted to sacrifice me, so that he could lift a curse placed on him. I've done a lot of things since then, to survive, acts I wish hadn't been necessary to do so, to escape him. And now he's here.
That sounds like a long and complicated story lies behind it. My own is longer, too, and innocent people were hurt along the way, but I hope you will not come to despise me.