Whizbang Dustyboots said:I'm sorry, I think the OP meant to provide a link to Cities of the Underworld, but even then, that'd be for D&D DMs, not "true rpger," which encompasses way too broad a field to insist on a One Show Fits All thing.
Cities of the Underworld fits into just about any RPG setting that has cities in it, not just D&D.
Shadowrun, Earthdawn, World of Darkness, Ars Magica, D&D, Paranoia (which already has a supplement for it), Star Wars, Runequest, Exalted, Babylon 5, Star Trek... it doesn't matter.
Even Bunnies and Burrows or Teenagers from Outer Space.