>>107063612There may or may not have been a real Lucifer way the fuck back when. But all of the various hells are split from some ancient large single hell. And all the hell lords are pieces of the first demon. They are in competition with each other but they do not often fight each other. Not all of those guys in the pic are actually demons. Some are just really inhuman monstrosities that happen to rule their own dimensions.
They are basically the demon version of the god pantheons. Each hell is it's own dimension with it's own ridiculously powerful ruler called a hell lord. Like how each godly realm had a really powerful ruler called a skyfather. They are not really official places of punishment or afterlives, but the demons will collect up souls to increase their powers from time to time.