Hi. I'm Kate, and I'm going to start with the confession that I don't watch SPN and never really did. So I'm not sure what your critter may or may not like about mine.
First there's this lady, Susan Sto Helit, from the Discworld books. Technically, she's a duchess. Also, technically, she's only mostly human and a little bit immortal. Occasionally, she's filled in for her grandfather, Death. She's pragmatic and a bit snarky, and she's got a special sort of gift with anything that's stick-like: swords, hockey sticks, scythes...
And then there is Harley Quinn (miss_q), from Batman: the Animated Series. She's criminally inane. That pretty much sums her up right there. She likes to have a good time, and if she gets to cause a bit of mayhem in the process, all the better. She's from the tv show, rather than the comics, because I didn't want to play her that dark.
You can find their applications in their journals, you should be able to see them because Dean has been friended. And if you want to play with either of them, just holler, I'm up for any plot!