Yeah. [...] I've been here almost two years, and I still don't believe that anyone here created my universe. They do have the information on it, though. So no, it doesn't feel all that strange-- it's useful. But if you'd rather hear it from me, here's the basic idea: demons are corrupted human souls that have been to hell and had their humanity carved away. They look like black smoke when they're just floating around on their own, but the smoke gets inside people and possesses them. At that point, they become super strong and fast, telekinetic, nearly invulnerable to harm (though attacking them definitely harms the person they're possessing), except to pure iron, salt, holy water, exorcism, and certain special weapons.
That's good to know. Being super tall and having their vulnerable spot near the top of their body does make them difficult, if you can't fly. We probably don't have that here, though. Unless you think you could invent it again yourself?