Alternate Dungeons: Infested Sewers

Sewers are a vital part of any large community. They help prevent disease by filtering out waste and give excess water accumulated during a rainstorm somewhere to go instead of on the roads or into a citizen’s basement. But sewers also attract a certain amount of danger, be it annoying beasts like skittering rats or terrifying monsters such as otyugh dwelling mere feet from the populace.

Knight and Rats

By Bradley K. McDevitt


These creatures’ presence is seldom deliberate; instead they crawl, squirm or barge their way into the sewers in search of food or shelter. And when they nestle in and begin to breed, that’s when the infestation begins.

This supplement provides GMs with advice for transforming the infested sewers under their towns and cities into an unforgettable dungeon.

Extract: Infested Sewers Dressing

Use this table, to generate minor points of interest for the infested sewer:

  1. Rattling chains and desperate cries come from behind a wall. If investigated, treat this as a bleeding walls haunt (CR 5).
  2. All olfactory sensations are reversed in one section of the sewer, causing horrid smells to be perceived as delectable and pleasant smells to be perceived as pungent (DC 12 Will negates).
  3. A trail of gore coats one of the walkways. If there are no walkways, it instead lines one of the walls or ceiling.
  4. All of the rats in the sewer are missing paws, ears or their tail and dead rats with more severe wounds litter the floor.
  5. Part of one of the walls appears to have been burned, as if by alchemist’s fire.
  6. The constant chattering of vermin echo throughout the sewer.
  7. Humanoid footprints are visible amidst the filth.
  8. An odd animal sound echoes throughout the sewer (grunting, growling, croaking etc.)
  9. A dead creature with a monstrous chunk of flesh missing from its neck lies dead in the sewer.
  10. Part of the sewer’s lining is broken, creating a small whirlpool. The waterways in the room are considered stormy water (DC 20 Swim).
  11. A severed humanoid hand lays discarded directly underneath one of the sewer’s manholes.
  12. Scratch marks are etched into sewer’s stone floor. They appear to be made by large, powerful claws.
  13. Vile chemicals have polluted the water, granting all creatures living in the sewer a random animal aspect, as the spell. PCs who make contact with the water must make a DC 12 Fortitude save or become mutated (–2 to a random ability score) while in the sewer and for 24 hours after leaving. This mutation is a polymorph effect.
  14. A section of the sewer’s wall is missing, as if something had clawed a hole right through it.
  15. A massive nest sits within a shadowy part of the sewer. It is built from large branches, muck and humanoid bones.
  16. One hallway in the sewer is lined with 1d6 everburning torches.
  17. The underside of a sewer’s manhole cover is encrusted with 1d4 precious gems.
  18. Tiny, red eyes glimmer within every shadow but dart out of sight before they can be focused upon.
  19. One of the sewers walls is inscribed with the gylphs of a magic circle against evil spell (DC 23 Knowledge [arcana] identifies). The gylphs have long-since lost their magical powers.
  20. The sewer floor is covered with a strange moss that glows as brightly as a torch when stepped on (and for a few minutes afterwards).

Related Resources

Praise for Alternate Dungeons: Infested Sewers

“…a fun pdf that all DMs (and players) who are bored by non-descript sewers should get…”

–Endzeitgeist (five stars + seal of approval)

A Pathfinder Roleplaying Game Compatible GM’s Resource by Alexander Augunas

Released 23 October 2014; Pages 12

PDF ($2.45) d20pfsrd, DriveThruRPG, Paizo, RPGNow, Warehouse 23

Download a Free Sample Infested Sewers: An Alternate Dungeon


Alternate Dungeons: Infested Sewers

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