Tuesday 17 February 2015

Fantasy City Sewer Generator

Overpopulated metropolises require bizarre, busy and labyrinth underground sewage systems that invariable lead to caverns and long forgotten, buried remnants of older settlements.

Bexley's  underground is unfortunately under siege by Wrecktown Terrorists (Rat-like men, with an affinity for fire and bones, who proclaim the rule of a forgotten, ancient king). City dwellers too weird and uncomely to find shelter in crowded Lower Bexley may eventually slip underground for accommodation.  Rumors of other strange beings engaged in construction and excavation also abound, as well as talk of large natural caverns and water bodies. The Bexley Port Authority requires help dealing with the former and information regarding all of the latter.

Below is a set of tables I plan to use to create random sewer rooms between pre-prepared dungeons beneath the city, or if the PC's decide to pull up a random city street sewer grate and jump in. As such, this generator is intended to be a stopgap generator of sewer adventure spaces, a side dish or condiment more so than a main meal!

(Here's some monsters and an encounter table for any Sewers you might generate.) 

Cavernous Old Kingdom Ruins, bonfire burning.

Fantasy City Sewer Generator:

Entrance Type, d6:

1) Broken, smashed-in, twisted or otherwise easily passable Sewer Grate.
2) Slime covered, rotten, soggy wooden door. Some rusted iron re-enforcement (25% chance of being locked).
3) Moss and slime covered stone door, iron latches/handles (50% chance of being locked).
4) Complete sewer grate, bars approximately half a foot apart.
5) Crumbled stone masonry, evidence of old pillars or door. Covered in general slime and muck.
6) Running water, waterfall like curtain.

Entrance Trapped? (25% Chance). 

If Trapped, Trap Type, d4:

1) Pressure plate, releasing stone and iron debris (Save Vs. Paralyze, d6 damage).
2) Trap door to flooded pit (hidden beneath water or debris).
3) Trap door to spiked pit (d8 damage from spikes), may also be flooded (Hidden beneath water or debris).
4) Pressure plate, releasing toxic dump of sewer waste (Save Vs. Disease, consult disease table of choice).

Number of Exits = d4. 

Room Shape, d4 (Roll twice and combine into new shape):

1) Circle.
2) Square.
3) Rectangle.
4) Triangle.

Room Size, d4:

1) Tiny, bedroom, hole like.
2) Medium, Hallway, living room.
3) Large, Dining room, ball room, courtyard.
4) Huge, Field, cavernous.

Light Conditions and Source, d6: 

1) Pitch black, no source.
2) Very dim natural light.
3) Well lit, oil lanterns, hanging on walls.
4) Very dim glowing mushrooms or other flora.
5) Very well lit, bonfire burning.
6) Dim, spluttering torches (threatening to go out).

Room Type, d8 (Would make sense to maintain a Room Type for a number of rooms, rather than re-rolling each time - creating semi-logical "zones"):

1) Operational sewer. Flowing sewage/water. Iron ladders and walkway.
2) Wrecked sewers. Flooded or drained. Broken ladders, shattered walkways.
3) Sewer operation room. Pipes, valves, tools. May control a gate or valve close by. Possible ladder to surface and armed Bexley Port Authority guards.
4) Old cellar or basement, possible boarded up entrance to an above ground building. Close to above ground occupied buildings.
5) Natural rock cavern, granite or limestone.
6) Freak/outcast/monster shanty town. Wood construction, bridges and shacks. Not necessarily inhabited.
7) Natural water feature, river, pond or lake. Possible flora growth.
8) Old kingdom masonry. Impressive arches and columns.  Friezes illustrating skulls, skeletons and large crowned skeletons. Bone effigies/jewelry may be strewn about, along with evidence of recent fires.

Room Descriptor, d8:

1) Extra water, flooding or high water level.
2) Signs of recent habitation, debris, refuse, burn marks.
3) Sewage intake, flows in from pipes or ceiling. May affect water flow direction. Probably stinks.
4) Sewer controls or operations, pipes, valves, cages, tools, etc.
5) Abandoned and rotting goods, furniture, trade goods (Roll on Table Y, Aspect for ideas).
6) Make shift camp site (3 in 6 chance of random encounter table based inhabitants being present).
7) Death or disease (Roll on Table Y, Aspect for ideas).
8) Old kingdom alter or large bone effigy.

Contents, d10: 

1) Monster.
2) Trap (See above Trap Table and double damage/general nastiness).
3) Disease (Roll on Table Y, Aspect or Disease table of choice), trudging through sewers is bad for your health.
4) Monster and Treasure (Table X for container, Table Z for contents).
5) Empty, 25 % chance of disease (Roll on Table Y, Aspect or Disease table of choice).
6) Empty.
7) Empty.
8) Hidden Treasure (Roll on Table Y for ideas, Table X for container, Table Z for contents).
9) NPC.
10) Non hidden treasure (Roll on Table X for container, Table Z for contents).

Table X, Containers, d6:

1) Bone pile.
2) Rotting, stench sack.
3) Chest, rotting, wood (10% chance of being locked).
4) Chest, slimy, stone (25% chance of being locked).
5) Hinged, hollow mushroom (5% chance of being ambulatory)
6) Hinged massive bovine skull.

Table Y, Aspect Table, d100: 

00-9) Good/holy/light
10-19) Air/ethereal/wind
20-29) Tiny/invisible/intangible
30/39) Value/thought/internal organs and reflection
40-49) Water/equalization/cleansing
50-59) Wild/bestial/nature
60-69) Fire/destruction/limbs and external action
70-79) Monstrous/gargantuan/enormous
80-89) Deep/earth/solid
90-99) Evil/profane/darkness

Table Z, Treasure, d100: 

0-25) Gold (See Treasure Value Table below).
26-51) Trade goods (See Treasure Value Table below).
72-77) Gems/jewelry (See Treasure Value Table below).
78-99) Magic item.

Table Z2, Treasure Value, d100: 

01-35) 75 x 1d10 GP
36-65) 150 x 1d10 GP
66-85) 250 x 1d10 GP
86-00) 1000 x 1d010 GP


  1. that first sewer is either not a sewer and is a reszervoiure(bud spilling?) of some kind or it is a sewer which belongs to an extremely rich person/king/emperor with a sewer fetish.

    1. You are right! The photo is of Basilica Cistern, which is obviously a cistern not a sewer. It is a wet underground man made place, and I love columns, so I had to include it.