The dread city of Carcosa

Carcosa is a dark kitchen-sink fantasy by Geoffry McKinney, that mixes science-fantasy, sword & sorcery and cosmic horror. The setting takes place on another planet and at an unknown era. Carcosa is not the name of the world, but is the name of a mysterious alien city. The setting was inspired by the works of H.P. Lovecraft, Clark Ashton Smith, Robert E. Howard, A. Merritt, Jack Vance, and David Lindsay. The original game was a mix of 1st edition Gamma World and 1st edition Advanced Dungeons & Dragons.

The setting is highlighted by:

  • A pantheon made-up exclusively of H.P Lovecraft's Cthulhu Mythos.
  • An alien world with two moons (one is green), and three strange colors (from David Lindsay's A Voyage to Arcturus): Dolm, Jale, and Ulfire
  • Humans of various — pronounced and vivid — skin colors: Black, Blue, Brown, Dolm, Green, Jale, Orange, Purple, Red, Ulfire, White, Yellow and Bone (their skin and flesh is transparent to the bones).
  • Humans are at the bottom of the food-chain (see below).
  • Removal of high-fantasy/mythological races and monsters (elves, fays, manticore, angels, etc.) in favor of pulp-fantasy/Lovecraftian creatures (Illithids, aliens, mutants, dinosaurs, icky/slimy/oozy/wormy/tentacle-rape horrors, etc.).
  • Alignment divorced from ethics or morality (see Alignment: Cosmic Law and Chaos)
  • Complete removal of traditional "Vancian" styled magic (fireballs, read magic, color spry, etc.) in favor of occult-styled spells cast with flavorful sorcerous rituals that requires long quests and brutality imposed on helpless victims.
  • Retro "B-movie" sci-fi relics left behind by alien "Grays", and strange artifacts of the Great Race - both have to be figured-out by the Player Characters.
  • Radioactive substances akin to The Colour Out of Space and comic books.


"The sense impressions caused in [an observer] by these two additional primary colors can only be vaguely hinted at by analogy. Just as blue is delicate and mysterious, yellow clear and unsubtle, and red sanguine and passionate, so he felt ulfire to be wild and painful, and jale dreamlike, feverish, and voluptuous."

— David Lindsay, A Voyage to Arcturus, chapter 6: "Joiwind"

"[Dolm] stand[s] in the same relation to jale as green to red." "[It is] a compound of ulfire and blue".
— David Lindsay, A Voyage to Arcturus, chapter 18: "Haunte"

Carcosa map1

A colored map of the setting (click for larger view)

Carcosa is the name for a strange alien city on a nameless planet 153 light years away from Earth, orbiting a star in the Hyades Cluster. Carcosa stands on a lifeless island of black stone on Lake Hali. It is billions of years old and impervious to the weather. As such, it is still intact. No one, not man nor beast, dwell there, save for the dark mysteries that permeates the empty halls, and the fools who seek such terrible truths. Enter at your own risk!

Humans are not native the world. Long ago, an extinct race of Snakemen brought humans form another planet (possibly Earth) to the alien world to serve as slaves and lab-rats. Once the Snakemen died out, the now feral humans escaped and infested the world like rats. That happened so long ago, the Snakemen are largely forgotten by humanity.

Most humans live in secluded niches, away from each other, as well as the strange technology, sorcery, and monsters that permeates the world. Humans hide and survive mostly thanks to being too insignificant to factor in the food-chain. Communities are usually small, usually around 300 people, and lead by a powerful (high level) individual. Leaders bare names (or titles) that are lavish in description, like "His Beneficent Dominance", "The Inestimable Height of Slender" or "The Apotheosis of All Excellences." The technology level of their arms and armor tends to be that of early 6th-century England.

Humanity is not alone on the planet. There are alien "Grays", and a whole host of Lovecraftian races: Primordial Ones, Shoggoths, Mi-Go, The Great Race, The Deep Ones, and the B'yakhee. Although, they are rare encounters, they left plenty of ruins and space craft to be explored.

Alignment is defined solely by one's stance towards the Great Old Ones (like Cthulhu, Hastur, Yog-Sothoth, et al.). Nothing else is considered, as it does not define ones' morality, ideology, or allegiance. People with opposing alignments are not automatically enemies and can peacefully coexist with each other. If the Great Old Ones were to be released from their imprisonment, Chaotic characters would aid these dark lords, while Lawful characters would fight them akin to the Battle of Ragnarök, and Neutral characters would just avoid the conflict all together.

The native life on planet is dangerous and horrific beyond imagining. Something like an orange and purple tyrannosaurus rex with toxic gas breath and eyes that emit beams of concentrated radiation is not that common, but its not all that unusual.

The main appeal of the setting is with the game's starkness, strangeness, and uniqueness. The setting is also so ambiguous with history and cultures, that it leaves a lot of room for creative Referees (OD&D term for Dungeon Master) to add their own ideas to what can be found, in a near-open-sandbox way, thus allowing the game to vary form play-group to play-group.

Rule SystemEdit

Carcosa comes in two editions: The original "Supplement V" edition booklet; and the current hardcover "LotFP" edition.

Supplement V: CarcosaEdit

The "Supplement V" booklet presents itself as a "Book of Rules Option for the Original Fantasy Role-Playing Games Published in 1974", in other words "The unofficial fifth supplement of Original Dungeons & Dragons." As noted, this edition uses the original 1974 Dungeons & Dragons rules as the core rules. There are no rules to distinguish the races, and classes are limited to Fighting-Man (OD&D term for Fighter) and Sorcerer. Unlike a D&D Magic-User, a Sorcerer do not start with any spells — spells are discovered during play — and may use any armor and weapon as Fighting-Men. Save for a x1.5 difference in needed Experience Points per level, The Sorcerer class is mechanically identical to Fighting-Man in every way. There is a slim chance that characters can possess mental powers called psionics. Psionics are unusual in the way they can change from day-to-day. The systems is as follows:

At first level, roll d% to determine if a character possess psionics. Determine the chance by adding each of percentages that applies. (e.g. A character with 17 Intelligence, 10 Wisdom and 15 Charisma has a 4.5% chance of possess psionic powers. A maxed-out character with 18 Intelligence, Wisdom and Charisma has a 12% chance of possess psionic powers.)

The following chances are competitive (added together).

15 0.5% 1% 1.5
16 1% 2% 3%
17 1.5% 3% 4.5%
18 2% 4% 6%

At the start of each day, the player roll a d4 to see the number of psionic powers that are available to his character that day, while the Referee rolls a d8 (or some other die, if more powers are used) for each psionic power available. The number of times a character can use psionic powers per day is based on level. The character can use any ability known within the limit of the times a day psionics can be used.

Level Per Day
1-2nd 1
2-4th 2
5-6th 3
7-8th 4
9th+ 5
List of Psionic Powers:

1) Clairaudience (as D&D spell)
2) Clairvoyance (as D&D spell)
3) ESP (as D&D spell)
4) Mental Blast
5) Mind Control (as Charm Person spell)
6) Precognition
7) Telekinesis
8) Telepathy

To account for the fact the OD&D used exclusively six-sided dice for Hit Dice and Damage Dice (the iconic polyhedral dice were not widely available at the time), the rules accounted for variable dice by having the Referee randomly determine which dice to be used that could change on an encounter-to-encounter basis. This can create an unusual power-balance that makes determining the outcome of combat difficult to predict, although given the general hardship of the setting, players are advised to employ better strategies than all-out attacks. The systems works as follows:

Type of
1-2 d4
3-4 d6
5-6 d8
7-8 d10
9-10 d12

Carcosa: Lamentations of the Flame PrincessEdit

The hardcover "LotFP" edition is based on James Raggi's Lamentations of the Flame Princess Weird Fantasy Role-Playing rules.


The Carcosan GrimoireEdit

This is a fan-made supplement for the first edition supplement. It list a number of fan-submitted content.

Conversion NotesEdit

Using the Mutant Future rules to run Carcosa is not that difficult. In fact, its one of the easiest system to run with Carcosa as both games assume Fighter as the playable class, and both games make use of radiation, mutations and mysterious technological (and alien) artifacts. The main change — as would be the case of converting any D&D-based game — would be the higher number of hit points at the start. Given the dangerous and unbalanced nature of the setting, this is would be a great benefit to players.

Here are some basic ideas of conversion:

  • Humans are not like Pure Humans form the MF rulebook. In fact, they are generated like Mutant Humans, but without mutations (you can still gain them during play). Racial Modifiers can still be used with humans that show no outwardly signs of mutations. Likewise, due to the innate xenophobia so common through out the would, negative adjustments are applied to anyone not the same skin color as the character, more so anyone who looks like a Sorcerer (who tend to use people in their depraved rituals) and Bone-Men (who are considered abhorrent feinds). Bone-Men have the benefit form 80% invisible in dark (like a Nehwon Ghoul).
  • Androids, Mutant Animals and Mutant Plants are not playable races.
  • Characters roll to see if they possess psionic powers as above. If successful, the character gets 1d4 Mental Mutations. (Mutations do not change from day-to-day, and their use are not limited by level) Characters also have a 15% (or any other number the Referee feel right with) chance of possessing 1d4 Physical Mutations.
  • The Food Vendor Wares list found in the rulebook are not used (food in this setting is way more exotic, but largely unstated).
  • Sorcerers in Carcosa progress at the same rate as a Mutant Future character (needing 3,000xp to advanced to second level). But to make the game easier to run, use the standard Mutant Future Character Level Progression table, but have Sorcerer characters loose 15% earned experience. As noted in the Carcosa rulebook, Sorcerers do not start with any spells — finding them are adventures of and onto themselves!
  • Monsters usually have additional Hit Dice to account for the player character's greater Hit Dice. There are no hard formula to adjust D&D-based monsters to MF monsters. The easiest method is to add 2d4 to a monster's normal HD, but a Referee is free to use what approach he feels works best.


  • The original Supplement V booklets were produced in limited quantities by McKinney himself, before he discontinued the booklets due to the labor involved.
  • Due to some controversy with the methods required to cast spells — which includes graphic examples of rape, torture and infanticide — McKinney released an abridged version of the Supplement V booklet.

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