Call of Cthulhu

Call of Cthulhu
RPG published by
Rule System Basic Roleplaying System
Authors Sandy Petersen
First Publication 1981

Call of Cthulhu is a roleplaying game based on the writings of H.P. Lovecraft, in which the player characters are more or less normal guys who might be able to fire a pistol without killing themselves. They try to find the truth of all existence. In the course of their investigations, the players might find themselves fighting horrors from beyond space, such as Cthulhu, who eats 1d3 investigators per round and is generally cranky after being woken from millennia of slumber.



Call of Cthulhu uses the Basic Roleplaying System (BRP), first used in Runequest and also for Stormbringer, Elfquest, and a variety of other games. It uses an array of D&D-style attributes (STR, DEX, INT, CON, POW, EDU, APP, SIZ) rated on the familiar 3-18 scale, plus around 60 skills rated as percentiles.


To perform any action, roll d100 and try to get under your skill; rolling 1/5 of your skill is a critical success, or an 'impale' on an attack. Used skills are marked and at the end of the adventure may increase by 1-3 points if you succeed in rolling under the inverse of the skill. This leads to very gradual and organic character progression, and encourages players to use as many of their skills as possible at least once per adventure. Attributes are checked in exactly the same way, though are typically multiplied to make the check passable, typically by 5. Another option is comparing them to an opposing score on a resistance table, for every point of difference the check is 5 points easier or harder, and 10 points difference is either an automatic success or failure (for example, someone with 10 STR trying to bust a door in with 12 STR has a 40% chance of doing so). Damage is handled via hit points, which for PCs never advance beyond the region of 10-20, though if they can justify it to the keeper they can get armor.

Character GenerationEdit

Chargen is a relatively long process due to the number of skills and the percentile values, although the free program Byakhee is available to speed things up. You roll attributes, select a profession, gain a bunch of skill points to spend on your professional skills, (such as archeology or painting) then a bunch more to spend on your hobbies. For instance, firing Tommy-guns (which definitely ISN'T a total waste of points).


Investigators are typically unable to go toe-to-toe with the monsters in CoC, so most of the game consists of investigation, exploration and gathering clues, with the investigators typically finding something they can do to either destroy or banish the thing that has been ravaging the area. Imagine Scooby-Doo, except with eldritch, inter-dimensional horrors that will almost certainly kill you or drive you mad (so basically imagine the Scooby-Doo Mystery Incorporated finale), and who are impervious to most weapons humans can muster outside of a goddamn Howitzer (or a passenger ship, or everyone with a boomerang) to deal with (though, shotguns should work for anything roughly man-shaped), rather than Old Man Withers dressed up as a ghost to scare away the locals.

If you are lucky your investigations will allow you to reach any sort of confrontation armed with magic (which, you guessed it, drives you insane to use), a list of the creature's weaknesses, or at least a metric fuckton of dynamite. Spot Hidden and Library Use are two of the most commonly used skills and any player that thinks a gun is useful for anything other than intimidation will be having a fun time swimming inside a Shoggoth or using it on him/herself to stop the voices.


Sanity or SAN represents your mental stability. It is capped at the inverse of your Cthulhu Mythos skill; that is to say, you cannot know what is really going on and remain sane. When you experience something terrifying you make a SAN check; if you fail you lose a random amount of SAN, and often a small amount if you succeed as well. If you lose a substantial amount (five or more in one go) you can have a panic attack, flee or any other sort of madness, though you have to roll to repress the memory of the thing you see first. If you lose a very large amount (one fifth in a game hour) you can develop phobias, mental conditions, or go insane for months on end. If you run out entirely you become an NPC, who may go insane and gibber in a corner for the rest of his life, or he may go and join the bad guys. It's not all bad though, as going insane from something mythos-related actually gives you insight into the thing you have seen.

Sanity loss is a source of both frustration and good roleplaying opportunities, as on the one hand playing out multiple personality disorder can be good fun. On the other hand being trapped in a hole with a monster is bad when one character has a darkness phobia and is curled up in the fetal position, one is claustrophobic and has fainted and one with a snake phobia who refuses to use the rope to climb out can be either frustrating or Fun for player and keeper alike.


CoC is set in the world of Lovecraft's Cthulhu Mythos but incorporates many of the inventions of later writers and the revisions of August Derleth. The historical setting is the 1920s, the era when Lovecraft wrote most of his work, and although modern adventures are possible (and have had a healthy amount of official support over the years), the Jazz/Classic era has several advantages, such as the lack of communications, the fact that parts of the world were still unexplored, and the plausibility of just about any adult male having military experience from the recent World War.

There are also expansions to set adventures in the days of ancient Rome, Dark Ages Europe, Revolutionary France, the Wild West, Victorian Britain, World War II, and the far future, as well as the fantastical Dreamlands and post-apocalyptic settings (just in case your adventurers in the 1920s failed to stop R'lyeh rising from the deep or the forces of Nyarlathotep from opening the Great Gate). However, these settings are much less used.

The premise of Lovecraft's world is that we live in a small circle of firelight and sanity created by human civilization, and beyond that circle, the universe is dark, uncaring, and full of things with tentacles and too many eyes. Our science doesn't properly describe the universe, and to understand the true horror of reality is to go mad. Before the rise of our civilization other, non-human things owned the world, and after we fall they will own it again.

In terms of physical location, the (fortunately) fictional city of Arkham, Massachusetts is a common setting. Arkham is an amalgamation of several New England towns and contains all the massive libraries, decaying colonial houses, faux-gothic estates and inbred lunatics that one could want for an American horror setting. There is also Arkham's Miskatonic University, an organization with a worse safety record than the fucking Umbrella Corporation. If your character is a professor, he likely teaches at Miskatonic, and will therefore surely die.

CoC on /tg/Edit

This joke is older than most of you assholes reading this page.

Call of Cthulhu is consistently popular among gamers. "Roll for SAN loss" has inevitably become a meme, used in place of "ARGH, MY EYES" or sometimes "MAN THE HARPOONS".

See AlsoEdit

  • Trail of Cthulhu, an updated version of the game using the GUMSHOE system.
  • Delta Green, a modern-day campaign setting for the game, in which the player characters are various military or government employees.
  • Old Man Henderson, the only man crazy enough to ever defeat the Great Old Ones at their own game.
  • Gunslinger Rick, he shot Cthulhu back to R'lyeh. Then left to smoke a cigar. He didn't win, not on the scale of Old Man Henderson, but he did give humanity another couple of million years

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