Vampires are real. We all know that. They can't turn into bats, or wolves, or mist, but they're here. I think we're all pretty comfortable with the idea that myths are based on some kind of reality, and the more they appear the more likely that thing is tangible. Vampires are real.
And if they're real, they're terribly lonely. You have your standards - basically long-lived humans who drink blood and can't tolerate sunlight, and that's great, except 120 years is long enough most humans don't care to stick with it, let alone 200. You could say the hunger drives them, but let's face it, if you're reading this, hunger probably isn't enough. So you'd want company, and that means at least two vampires, if you manage to find your soulmate/bromancer on the first try, drinking a pint of blood each a day, so you need 120 adults (x2 with kids and old folks) to support your unlife (ask the red cross if you don't believe me).
If you have powers, you need more, say 3 pints because of your eternal struggle against werewolves, the IRS Estate Tax division, and all the creepy shit that crawls out of the sewer at night. To you, a standard is pretty much as bad as the cattle. You need a peer. So there are 2 of you and 40 standards living off a community of 5,520 human beings.
But you still need to find each other.
After half a century of surviving well-meaning neighbors and less well-meaning pitchforks, you're subtle. If vampires didn't need subtlety, they'd be lording it over all of us from gothic castles. So you're moving through the multitude, trying to act like everyone else, trying not to react to the thoughts you can read or the thousands of social cues that you've studied for decades of watching, waiting for the other vampire to slip up.