But don’t demons have an easy time returning to the abyss regardless of where they are as they are literally bound to the plane and can will themselves back unless actively bound, and this still can’t bind them if they suffer enough damage. Demons would do great in some high tech civilizations as they might people to pass off as another race with unknown tech, who would make great bankers, as nobody could find their bank and they are greater at following their interpretation of their own words. Though it’s interesting that god’s aren’t affected by native mana level, implying they are bound to their god pool, as demons are to the abyss, if anybody could figure out how to tap into abyssal power they would be nigh unstoppable, as a demon anyways. Near as I figure the abyss is an abyss that tends to suck anything that enters it to places beyond reach unable to escape.
Also how common are telepathics in the tech/magic worlds that are just right as mentioned earlier?