In Invisible Sun (and Amber), you’re told that yours is the real world, and anything resembling our own world is just an illusory “shadow,” or reflection, of that true reality. So, you know, screw those worlds’ people. Use them as servants or soldiers or whatever. Not like they’re real people, those works say.
I have enjoyed reading Invisible Sun and Amber, but their authors don’t seem to realize that this sounds creepily like how slavery and oppression have been justified in real-world history. Illusorati sets up the same dynamic— a city of powerful magicians and world-walkers who think they’re at the center of the universe — but says it’s been over 100 years since it was legal to enslave people from other worlds. That doesn’t mean that inequality and oppression against those people just disappeared, though. The game is more overtly political in its aims and its characters’ pursuits.