Need a quick city dungeon? You can follow this five-step random generator to create an entirely random dungeon shell you can fill in and personalize until your heart's content!
The entries are deliberately somewhat vague to allow more GMs to use them, as they’re open to incorporating varieties of monsters with varieties of challenges on most outcomes.
While these reference monsters from D&D, the results can work at most fantasy RPG systems beyond D&D.
1. Where is the Dungeon?
The following table determines where the dungeon is within an urban environment:
City Dungeon Location Table
| d12 | Location |
|---|---|
| 1 | Within a largely abandoned warehouse district |
| 2 | In a chaotic city market in a poorer region of town |
| 3 | Through the sewers and below the central hub in the undercity |
| 4 | Built within a secluded upper-end district of wealthy recluses |
| 5 | Hidden within the large central clock tower |
| 6 | Surrounded by the city’s cemetery, patrolled by vigilant watchmen |
| 7 | Stationed in a ruined portion of the city, largely unpopulated and hazardous to humans |
| 8 | Built on the docks for ease of access to trading and smuggling ships |
| 9 | Stashed within cryptic ruins the city was built on top of when it was founded |
| 10 | Just beyond the city walls by way of a run-down cobbled road |
| 11 | At an abandoned construction project, left for years after a tragedy on site |
| 12 | In the city's arcanist quarter with nearby access to portal transportation |
2. What is the Dungeon’s Purpose?
The following table determines the builder’s purpose for this dungeon:
City Dungeon Purpose Table
| d12 | Purpose |
|---|---|
| 1 | The dungeon houses a seat of for a member of the criminal underworld’s ruling council |
| 2 | The dungeon is a military outpost that pushes out city authority for its ruler’s own |
| 3 | The dungeon secretly is a beacon for a behemoth monster and slowly calls it to the city |
| 4 | The dungeon provides a hideaway for common criminals and illicit dealings |
| 5 | The dungeon slowly washes out magical influence, converting the denizens to a dark god |
| 6 | The dungeon masquerades as a legitimate faction’s headquarters while housing a cult |
| 7 | The dungeon was built to hide a dangerous monster within the city limits |
| 8 | The dungeon offers a puppet master close access to the politicians they rule over |
| 9 | The dungeon houses experiments done on kidnapped impoverished citizens |
| 10 | The dungeon holds enemies of a criminal overlord’s agenda |
| 11 | The dungeon is a foothold for a rebellion group seeking to overthrow the government |
| 12 | The dungeon was here long before the city, acting as a lock on an ancient spell |
3. What is the Dungeon’s Structure?
The following table determines a general structure you can use to build your dungeon:
City Dungeon Structure Table
| d8 | Structure |
|---|---|
| 1 | An arcane university campus with a large central tower of learning |
| 2 | A lavish four-storied mansion expressing extreme wealth |
| 3 | A church with a tall steeple and bell that rings out at an odd hour and minute mark |
| 4 | A stone bastion floating above the earth, connected to the ground by a wooden walkway |
| 5 | A magnificent library with dim lights floating in spectral hands within |
| 6 | A small greenhouse within a flourishing garden maze |
| 7 | A band of unremarkable houses connected below by a series of master-crafted tunnels |
| 8 | A colosseum once used for gruesome bloodsport and cruel deathmatches |
| 9 | A penitentiary retrofitted for new diabolical purposes |
| 10 | A large ruined stronghold whose remains have been repurposed into a new buildings |
4. Who Currently Resides in the Dungeon?
The following table determines what kinds of creatures reside in the dungeon:
City Dungeon Creatures Table
| d20 | Creatures |
|---|---|
| 1 | Humanoids who call the city home but are wanted criminals |
| 2 | Woodland elves who view the city as a blotch on the world that should be cleaned |
| 3 | Dwarves plotting a grand excavation below the city that will endanger everyone |
| 4 | Orcs ousted from their tribe making a new life for themselves where they can |
| 5 | An extended halfling family of thieves who collect their ill-gotten gains here |
| 6 | Demons locked within by a now-dead warlock who got in over their head |
| 7 | Devils slowly weeding dissent into the city by dealing with the city’s leaders |
| 8 | Celestial aasimar on a devout crusade to purge non-celestials from the land |
| 9 | Oozes who’ve turned the dungeon’s past owners into goop |
| 10 | Unnaturally city beasts that seem to rapidly grow when exposed to the dungeon’s magic |
| 11 | Constructs crafted by a gnomish artificer who aggressively “clean” life from the dungeon |
| 12 | Fey tricksters bargaining known for their transformative pranks on the locals |
| 13 | Religiously zealous humans on a mission to expunge all other religions from the city |
| 14 | Enthralled humanoids beguiled by an enchanting villain to do their bidding |
| 15 | Dragonborn smugglers hiding a rare evil dragon egg |
| 16 | Fire elementals locked within to prevent a citywide disaster |
| 17 | A posse of lycanthropes who use the dungeon to safely transform to their true forms |
| 18 | Spirits of the victims who died at the hands of the dungeon’s creator |
| 19 | A reclusive beholder and its enthralled goblin lackeys unaware of what they work for |
| 20 | Undead villains who masquerade as living with illusion magic trying to kill the city |
5. What Rooms Are in the Dungeon?
Consider either rolling as many times as you’d like ahead of time to plot out the dungeon, or rolling as the players progress through where the new doors may lead. There are two options: an ordinary rooms table, for when you want the players to explore some mundane options, and extraordinary rooms for when you want to spice things up a bit.
The following tables can be rolled on to determine what rooms the players encounter as they progress:
City Dungeon Ordinary Rooms Table
| d12 | Ordinary Room |
|---|---|
| 1 | Prison cells used to contain enemies with a magic-detecting ward at its center |
| 2 | Armory housing weapons that help rally the denizens to the dungeon’s defense |
| 3 | Kitchen with ample dry ingredients, a stove, and water-elemental-based sinks |
| 4 | Bunks for the dungeon’s inhabitants |
| 5 | Tactical chamber with detailed maps of the city on the central table and walls |
| 6 | Library containing dusty books rarely touched and worn, dusty reading chairs |
| 7 | Infirmary with alchemical and mundane medicines and supplies |
| 8 | Vault storing strongboxes of gold and currency as well as an odd human-sized statue |
| 9 | Recreation room with a pair of card tables and dart board overlooking the sprawling city |
| 10 | Study with a wide window behind an elegant desk with several locked drawers |
| 11 | Dining hall with ample seating and long wine racks and barrels at the ready |
| 12 | Stables with common mounts for the region |
City Dungeon Extraordinary Rooms Table
| d8 | Extraordinary Room |
|---|---|
| 1 | Alchemy lab with vials boiling odd concoctions with bits of shattered glass on the floor |
| 2 | Arcanist study with books and wild instruments coating tables around a chalk circle |
| 3 | Crypt full of glass caskets, each showcasing a pristine skeleton within |
| 4 | Sacrificial chamber with four shackles holding a drained victim over a basin |
| 5 | Puzzle room with a series of books and padlocks keeping certain cages closed |
| 6 | Conservatory full of violent and exotic plants taken in from regions around the world |
| 7 | Underground dirt fighting ring illuminated by a long hanging lantern |
| 8 | Closed planar gateway covered in odd magical runes denoting fire and brimstone |
