Some demons has different kind of semi-species. Some grow a pair of horns but some has cat-like feline appearance. Some of them also has different appearances of tails, most often the female has heart-shaped while male has arrow-like structure.
All demons have pair of wings. Most of the times they can be seen used as aviation, but some instances, due to the fact that their wings are too small to fly like Purson Soi, they are not able to.
Connection to Humans
Since ancient times Humans and Demons have some sort of a pact.