Demons

Demons are spirits that have rejected the gods and the angelic hierarchy, unable to stomach the many rules that bind the Angels. They live in the 'wilderness' of the spirit realm, a dog-eat-dog world of constant competition and strife.

Nature and Behavior

Demons are not necessarily raging sadists, but they are aggressive, deceptive, and opportunistic—those that aren't are quickly weeded out. A demon has little empathy for anyone they don't share a personal bond with. They act on a whim, consider preying on the weak to be perfectly justified, and are obsessed with dominance. Having grown up in a violent realm, they see virtually every social interaction as a struggle for dominance and will attack for the slightest reasons.

To humans, there is little difference between this behavior and pure Evil. Set loose in the material world, a demon will create a trail of atrocities in its wake.

Summoning

Demons must be summoned to the material plane. Once here, they do not return until their vessel (an ectoplasmic shell, a puppet, or a possessed body) is destroyed. They accept life force and souls as payment, making them easier to hire than mages. Some ancient demons know secrets and restricted spells that many mages badly want to acquire.

The Silence of the Gods definitely created more demon summoners. Modern demons are bolder and more aggressive when dealing with angels, but because demons constantly fight among themselves, they haven't managed to inflict huge losses on the united angelic strongholds.

Demons are extremely proficient in soul warfare, far more so than humans, because they depend on soul magic skills just to survive on a daily basis in the spirit realm.