>>32105507You could steal some notes from science fiction stories.
Maybe they are ruthlessly cunning, in a Sparta "Strength above All" way that appeals to HFY people, but their losses in compassion means they can't befriend Ultra Beasts or normal 'Mons and work their way out of their hole.
You could treat them as living in Fallout shelters and that screwing with their mind. It lets you explore things more since you only have to explain why "those dude/ttes" are weird and not how an entire Civilization had to survive like that.