Hello, welcome to my ad. I'm Igloo, a long-time roleplayer with some limited experience on E. You can check out my O&O's, I think those are pretty representative of who and what I am. I just have one idea to propose to you all, and you can take it or leave it. And while I know this isn't the place for it, I'm willing to field this story in IMs as well as in forum play.
Have you ever read the Dresden Files or watched Constantine? (I know that's based on a comic, but I don't read comics.) I've got an urge for that sort of thing. The one guy in a mundane modern world who understands the things that go bump in the night (or the day) and has the means to shut them down. Those means, however, often including cutting a deal with the same paranormal element that he is aiming to put a stop to. That's where you come in.
You see, my character isn't a wizard, or a half-angel, or anything like that. He's just a guy who knows which monster takes silver and which one takes holy water, and knows how to track them down. But you can't prepare for everything, and some things are just too scary for an average Joe to take on, no matter how many apocryphal texts he's read in his spare time. He needs an ally who isn't so limited by mortal flesh, an ally who might not share quite all of the moral qualms that has led this do-gooder down his chosen path. She could be a genie, a demon, a sidhe, maybe even a vampire, but the point is she's only helping because it suits her purposes, and by relying on her, this investigator is unleashing an evil on the world that is only slightly the lesser. If he had any sense, he'd cut all ties, or even put an end to her, but he needs her, or at least, so he tells himself when he's too busy staring at her chest to think things through.
There are a few ways I could see this playing out. It could be very much a one on one game, with the story focusing on our characters' interactions with each other. Or alternately, it could take a greater focus on the 'cases' the investigator undertakes, which would lead to a greater amount of combat and, if I were to be completely honest, a chance for mayhem for your character. Whatever it is, it's important that you have at least a bit of a dominant streak in you, because you need to be able to do scary to scratch this itch. While this could technically come in a medieval fantasy setting, I'm definitely picturing modern, so you'd need to talk me into it if you have a strong preference for something else.
Anyway, hit me up via PMs if you think this might be your thing!