Some of our favorite bad guys are the Arch Devils and the Demon Lords. More people can name Jubilex than can name Erythnul, and that's no accident. Jubilex is just a little bit more awesome than any of the official Chaotic Evil Gods. Unfortunately, like many things related to the Lower Planes, there is substantial discrepancy available as to what exactly it is that these Dark Lords are. We suggest that you make up your mind and distribute this decision to your player characters.