In need of a D&D fix

[Geeklet]

Alright, first off, this will involve me, a male, playing a female character. Since I know that some people aren't fond of that sort of thing, I figured I'd put that little disclaimer out there and save them the time of reading the rest of the post.

Also, not looking for a strict Dungeons and Dragons game, as in keeping close track of character sheets, rolling for everything, etc. Just something based on the system and mythos, freeformed out.

First off, a little bit of info about the character I will be playing. A female human Warlock, mid-ish level (7-10, something like that), Chaotic Neutral. Unlike most warlocks, she never actually bartered with any sort of being to gain her powers, it was more something that was inherited from her family. She doesn't quite know this, or why they did such a thing, since she was raised as an orphan. She isn't really evil, like the majority of warlocks, but then again, their distrust of her nature has left her fairly jaded (thus the CN). In order to find out more about herself and what she is capable of, she spends time looking through ancient occult books that might give clues...

...But by doing so, draws the attention of someone she shouldn't. This person/thing is out to use her and turn her to their own evil whims.

So what I'm looking for is someone to play the corrupter. Obvious choice would be some kind of demon/devil, though it could also be an evil mage, or anything else you can think of. What exactly is after her and what purpose they want her for I can be very flexible with, just as long as the main element of corrupting the girl towards Evil is still there (Bonus points if you can go for something other than Chaotic Evil). Male, female, monsterous humanoid, etc., doesn't matter.