"Why do demons seem to constantly reveal themselves to me first!?"
The only other hidden demon in the game that I can think of was revealed when Selina jokingly guessed Nuriel was one.
@GWG Yes please. Just posted something so I may need to fix it.
It's okay. Let's see...I can give a more full summary later if you want, but right now I'm still catching up on all my games. I am in a lot.
Demons live in Hell. There isn't any central leadership (no Satan figure), but there are a lot of archdemons, demon lords, and the like--demons that lead because they are rich or powerful. Souls that go to Hell don't become demons, or money, or (usually) food; they simply exist there, often working for the archdemons as slaves but sometimes just being there for being shown off. Each demon lord has some set of qualities in souls that, should they be rejected from heaven (a whole different issue, which has more to do with "would they fit into the cogs of our machine" than "did he do good"), they will come. Demons temporarily exiled to earth often try to "corrupt" mortal souls one way or another so they can collect a fraction of the value of the soul once they return.
On the note of exiled demons...if a demon is on earth and not in Hell, either he is on a mission, or he is in trouble. The latter case is usually exiles, but I suppose it's possible for a demon to screw up so badly he willingly flees to Earth. (Or maybe Sen is the one in a few billion that doesn't like Hell?)
We need to figure out why Sen is on Earth, firstly.