Some time ago I ran an intense but short-lived forum game called Underdeep, a play-by-post strategic roleplaying game where the players adopted the role of subterranean rulers warring for control of an underground realm. Underdeep featured a pretty typical fantasy world – deliberately vanilla (Orcs, Goblins, Dwarves, Dark Elves, etc) – but while running it I found myself wondering about alternate possibilities for underground worlds…
The Great Effulgence burnt the world above to a cinder, and now only Blindghasts and gibbering Glowghosts dwell in the Lambent Lands above, lingering in the poisonous, glimmering wreckage of the megacities that once spanned the globe. But down below, in the vast, interlinked sewer systems of those incinerated metropolises, life survived and thrived. In the irradiated entrails of the earth, a seemingly endless labyrinth of pipes, passages, shafts, and tunnels, new societies have arisen, tribes of animals and people twisted by the same corruptive energies that desolated the world above.
The Ratkin are the most common – scabrous, plague-ridden scavengers and raiders who roam the tunnels in murderous Mischiefs, plundering and stealing, hoarding treasure in their feculent Middens. The various Molekin tribes dwell deeper, extending the sewerscape with fresh excavations. Perhaps most formidable of the Molekin societies are the Naked Queendoms, militant hive-realms dedicated to conquest and empire, though individually the dreaded psionic monstrosities known as the Starsnouts are more dangerous, telepathic abominations who delight in violating the minds and bodies of their enemies with their psionic powers and writhing nasal tentacles. Then of course there are the Gatorkin, a pack of depraved, inbred, albino lizard-people with an insatiable longing for raw flesh, the nigh-unkillable, survivalist Roachkin, the conniving Batkin, the revolting, carrion-feeding Flykin, the rabid Racoonkin, and the pallid, mewling Trampkin, warped descendants of the tunnel-dwelling homeless.
Yet these creatures are not the only denizens of the sewerscape. In the lower tunnels stranger beings stir. The seething horror known as the Wormhost squirms through the lowermost bowels of the world while the protoplasmic Filth Elementals self-assemble out of coagulate effluvia made animate by the puissant rays that scoured the surface. Deranged machines wander the deep places, pining for their former masters, while in certain ancient caverns of primordial origin the Wizened Ones groan in their dotage…
A handful: Necromunda, Redwall, Gamma World, Fallout, Metro 2033, Railsea.
I’ll be writing this as systems-neutral, but good systems would include hacked-up versions of Savage Worlds, Mutant Future, Omega World/Gamma World, d20 Modern, and probably lots of other systems.