I borrowed my backstory from the Dark Eye rpg. In Dark Eye vampires are beings cursed by the gods and have weaknesses specific to the god that placed the curse. So at the moment I'm itching to see what can be done ingame with the powers and weaknesses to fit the pantheon that I use in my simsworld (Ea and Maxis are their chief gods).
My first generation vampire, Marcus, was cursed in ancient roman times by Neptune, so his weaknesses will revolve around water. He can turn into batfish instead of bats, but this is only a story element for picture taking, of course.
Marcus turned Isabel, a spanish adventurer whom he had fallen in love with. Trouble was, Isabel fell in love with Arthur, a mortal warrior. Marcus didn't care, as Arthur would die after just a few decades. Trouble was, unknownst to Marcus Isabel secretly turned Arthur, thus creating a third generation vampire. While the other two are self-serving and hedonistic, Arthur won't turn down a party invitation, either. But he is also a man of ideals and seems a fitting candidate for the "good vampire" archetype, trying to stay as human as possible, probably even trying to convince the other two to atone and live out their lifes as humans.
These three were sealed in the forgotten grotto which I recently opened in my mainsave. Marcus already has had his first contact with modern civilisation in the form a nicely decorated fishbowl in one of my sims' house :D The other two roam freely and I'll probably let them do their own thing for a while, watching how they behave while I play other households.