Demons

Demons are sentient beings that dwell in the plane of hell (see planes of existence). They often travel to the mortal plane in order to extract chaos energy from mortals by interfering in their affairs and/or causing misery. Demons require chaos energy to sustain their lives and can live indefinitely by constant feeding and by avoiding being killed.

Demon Lords
In Euryale's Gambit, Igret makes reference to Demon Lords, but no details are yet given as to who they are.