|Art by Simon Roy|
The Weal (as the inhabitants now know it) is one of those places. After war and perhaps a period of utter barbarism, a roughly Medieval technology level society has emerged (amidst the half-functioning remnant of what came before) of androids (though they would think of themselves as "people," thank you): the artificial biologic beings once servants and playthings for the idle human rulers. Being an android has some advantages, not the least of which is the reality of resurrection, if you are attended to by the appropriate authority (i.e. super-user).
These post-human people have developed into tribes that carry some echo of their previous function: the clerics receive wisdom from the old god-machines, the fighters still hold as their sacred duty the protection of the Weal, and the wizards broker deals with spirits and command the various nanomachines and utility fogs gone quiescent or feral after their former masters forgot the eldritch codes to command them.
All these tribes or fraternities wind up battling monsters. Their is only so much space in the Weal, and the people need it. The lower, outer levels are the abodes of creatures once human (altered into strange forms by adaptive and cosmetic gememods gone wildly off model by natural selection unleashed), nanotech that will not be tamed, and in the outer, deepest levels there are posthuman sociopaths and grifters trying to break in.
The Weal is a dangerous place, but intrepid heroes can claw back the world from darkenss or die in the attempt.
Inspirations: Habitat, Starlost, Charles Stross's Saturn's Children universe, Numenera, Book of the Long Sun