They have various species of demons who differ in significant ways, functioning societies, traditions, organizations, long-lived cultures, well-governed countries/empires, and more advanced tech than humans. You do usually get some of that whenever authors don't just want to create the featureless generic horde of evil monsters #451651984985161, but how often do you get all of that together? And of course, there's no comparison with said featureless generic monster hordes.
