I actually waited for the dungeon getting settled (and distracted by other things too, and writer's block),

I already have an idea in mind. I'll put it to conform with the current situation. It's the dungeon building and the gathering of the imps, right?

I'll have my succubus to spin a cocoon and spawn her imps inside it. She might looked like human from time to time, but in a certain situation, she functioned like the queen of an ant colony (or wasp, bee, termite, or maybe Zerg... Tyranid?).