According to the system's definition, all the extraterritorial demons in this Taiyin Demon Cave are categorized as demons. Specifically, Li Fan encountered four types: demons, greater demons, super greater demons, and special greater demons.
...Okay, this naming convention is understandable; it probably doesn't refer to size, but to combat strength and threat level.
The ones in the shallow areas are the lowest-level demons, capable of creating illusions lasting about five to ten seconds. As long as one sees through the illusion, a snap of the fingers can kill them, slightly increasing the upper limit.
The greater demons are those that have seized a body to dwell in, usually some maimed and limbless corpses, tattered and leaking air from all over. A glance from the Crimson Pupils can kill them instantly. Their combat power is essentially equivalent to slightly stronger evil corpses, and killing them can increase the mood limit by ten points, significantly improving one's mood.