Demons of Karelon
Demons exist in a dimension called Karelon. Karelon is a place of constant violence and ever changing landscapes wrought by the Demon Lords that control and remake them to their liking. The border between the realm of Karelon and the World of Faelon can be manipulated and torn, allowing Demons to pour into Faelon, a place they love for its stability and space. Most of the inhabitants of Faelon hate the demons and attempt to eradicate them when they can. Others make pacts with them and help them cross over.