Hoo boy. This is a problem. SHE is a problem.
Mind, she has every reason to be pissy, and to be a problem, at least in her mind. She was just minding her own business, when some two-bit sorcerer summons her. She gets yanked out of her nice, warm, cozy home that she'd /just/ cleaned out(read, rid of other demons and other critters) and pulled to the cold human world, where some insolent little THING decides that he owns her. Hah. Well, that was amusing, at least. He didn't have a circle or anything, and, well, when she was done with him he became a smear.
However... however, she couldn't figure out how to get BACK! She couldn't sort out what she needed to do to send herself back. Sure, in theory she could kill herself here and she'd wind up home, but it's been hundreds of years since anyone summoned a demon to the mortal world properly. She's not sure WHAT would happen, and frankly she's afraid to try. However, it's not like she can ask for help, what with the running and the screaming.
And, argh, the screaming! That's another thing that pisses her off! She's minding her own business, and someone screams. First, it makes her hungry, so she eats the stupid bitch. Then ANOTHER person screams, and then another, and another, and she could eat them all, maybe, in theory, but her head's starting to hurt and the screaming's not stopping, so she grabs a car, and, well... you get the idea.
So she tries to keep to herself now, as much as she can. She's stranded, broke, and cold, and it's not even winter. There's not a damned thing she can do about it, either, or so it seems. Still, food is in plentiful supply, even if some of it is rather less easy to catch and eat.
As far as powers, Somilan is nearly invincible in most respects. Some things can hurt her, in theory, but they're in short supply. She's superhumanly strong, incredibly durable, and she can be pretty damned fast(by human standards) when she wants to be, with top speeds of fifty miles an hour and demonic stamina to keep up with it. Of course, she has high energy requirements, too... a person a day does the trick nicely, though.
In addition, well, she seems to have some magic. Like the ability to breathe fire, throw fireballs, and fly for a little bit, which is understandably distressing. As far as vore, well, she can do a LOT of things, with a particular fondness for plain oral, unbirth, and envelopment/absorption. If she's feeling nasty, though, she CAN be a herm.
And apparently, she has varying levels of armor she can summon. Hm.
Long story short? Unwilling(sort of) supervillainess, and in a state of permanent crankiness. Approx 5'6.