Historical Writing Prompt<< Could be a vampire murderer. And all the murders are actually bad people, but since it's a murder they have to figure out who killed them. Of course, the vampire is still alive, but no longer killing and Gabe it up years ago, and now just steals a food bag from the hospital every once and a while. And suddenly, when they're enjoying some food, they notice the headline of the newspaper and it's the face cream, a matching fingerprint, and a picture of them.
Scratch the vampire/human romance cliché and I think this could be a really cool thriller plot. Maybe the vampires went soft and lost their edge because they've ruled the world without challenge for so long, and then the humans begin hunting them to take back the world.