So I remember this game I had on my computer when I was younger.

It was a 3D FPS PC windows xp (at least it ran on it) that I played around 2009-2011 (but the game might have been way older since my country was behind the global technology).

You started in a mansion or castle and you could've chosen some characters if I recall and you killed monsters. It had some red meat monsters that if you killed they divided in two. At one point I think you got inside a dungeon with skeletons or whatever, I'm not truly sure. It caused me a bit of nightmares maybe. The game's menu page also had at the top a troll(?) face, 3D, moving the mandible clockwise, in a chewing manner perhaps.

If it's really old, perhaps it could be Ultima Underworld 1 or 2. It fits some of the criteria, having character creation, being FPP, and there is a demon-like creature on the top of the gameplay frame which responds to certain input such as when you kill a monster .. but that's in-game, not in the menu.

2009-2011 = old?

AHHHHHHHHH!!!!!!!

Oh wait, didn't see you qualify that.
Sorry. :D

That's a bit too old, my guess is that it MAY be made in 2006.
Edit: also didn't have character creation if i remember, just character selection