I would expect vampires(or any immortals) to have the political power to stop registration acts and the like form going through.
So modern world, sort of a mild science fiction. Maybe sort of a half masque. There's been events that lead people to believe in vampires, and there's a lot of rumors going around, it's a popular conspiracy theory, but traditional media still denies it or treats it like a joke. But in the past ten years belief has been gaining traction thanks to social media and cell phones(everyone has a camera). It's still sort of a "conspiracy" but it's not seen as batshit like lizard people. It's believed with maybe a little more frequency than people believing the moon landing was faked.
So, as such, there's "witch hunts" in places where churches and the like have a lot of sway. Vampires don't like the deep south or rural areas for this reason. Probably they often get the wrong guy, and end up burning staking an insomniac that they see walking outside at night too often.
Probably a pretty prototypical vampire? Stay in during the day, go out at night. Strong, fast, generally superhuman in every way, hypnotic(maybe just charming in general). Subsist on the blood of the living, it's best to get it from the same species as them. The "condition" is passed by a mortal drinking the blood of a vampire, or else it getting into their bloodstream(if they feel a little squicked out by drinking they can use a needle, but it might not be the best idea in that case).
Do they have any supernatural(as in, more than just superhuman) powers? Is there a difference in abilities between bloodlines? Are bloodlines a real tangible thing, or are they just a social construct in vampire society?
I'm also thinking that most of their human physiology still functions. Allowing them to eat drink and do drugs. Maybe it slowly goes away over time, so younger ones are very driven by human desires, but older ones are sort of otherworldly.