It's a bit confusing. I think where it gets muddled is, the ones that came to Earth with the purpose of mating and creating children were incubi/succubi, right? In the first lore chapter, it seemed like their offspring were just more succubi. If that's the case, where did the other physical demon lineages come from? Did other demons (non-succubi) visit later to have children as well? I thought that what made a succubus a succubus was that they came to Earth to make hybrid children.