Call of Cthulhu - Starter guide

What is Call of Cthulhu?

Call of Cthulhu is a tabletop roleplaying game of cosmic horror, investigation, and slow-burning dread. Published by Chaosium and based on the work of H.P. Lovecraft, it places players in the role of ordinary people - investigators, academics, journalists, doctors - who stumble upon secrets the human mind was never meant to know.

The default setting is the 1920s, a world of speakeasies and telegrams where the Cthulhu Mythos lurks just beneath the surface. Unlike most RPGs, Call of Cthulhu does not reward heroics. The monsters here cannot be defeated by the right spell or a high enough roll. The best outcome is often survival - and even that comes at a cost.

This is a game about fragile people in an uncaring universe. That sounds bleak, and it is - but it is also one of the most compelling and atmospherically rich experiences tabletop gaming has to offer.

How does the system work?

Call of Cthulhu uses percentile dice (two ten-sided dice read as a number from 1 to 100). Characters have skills - Library Use, Spot Hidden, Persuade, Firearms, and many more - each represented as a percentage. To attempt something, you roll under your skill value on a d100. Roll equal to or under your skill and you succeed. Simple, intuitive, and fast.

There are two key thresholds within each skill: half the value (for a Hard success) and one-fifth (for an Extreme success). These matter when the Keeper - the game master, called the Keeper of Arcane Lore - calls for more precise results or when opposed rolls are involved.

Character creation is skill-based rather than class-based. You choose an occupation - private investigator, professor, drifter, nurse - which determines your core skills, and then distribute additional points based on your character's background and interests. Characters do not level up in the traditional sense; skills improve through use, marked after successful rolls.

The central mechanic that sets Call of Cthulhu apart is Sanity. Witnessing horrific things - a body torn apart by something inhuman, a ritual that defies natural law, a glimpse of something vast and ancient - costs Sanity points. Lose too many at once and your investigator suffers a temporary or indefinite bout of madness. Lose enough over time and they are lost permanently. This is not just flavour. Sanity is a resource you manage, and watching it erode is part of the experience.

What do you need to start?

The core product is the Call of Cthulhu Keeper Rulebook - the primary reference for the Keeper. For players, there is the Investigator Handbook, which focuses on character creation and the investigator's side of the game. Technically you only need the Keeper Rulebook to run the game, but the Investigator Handbook is a worthwhile addition for groups that want players to have their own reference.

Chaosium offers a free quickstart called "Call of Cthulhu Quickstart Rules" which includes a condensed ruleset and the classic introductory scenario "The Haunting." This is an excellent starting point and available as a free PDF directly from Chaosium's website.

There is also a physical Call of Cthulhu Starter Set, which includes pre-generated investigators, simplified rules, dice, and several scenarios. It is one of the best starter sets in tabletop gaming and highly recommended for groups new to the system.

Who is this game for?

Call of Cthulhu is ideal for players who enjoy mystery, investigation, and atmosphere over combat and power fantasy. If your group loves building tension, piecing together clues, and roleplaying ordinary people in extraordinary circumstances, this system rewards that deeply.

It is also a strong pick for groups with horror fans, readers of weird fiction, or anyone who finds the Lovecraftian aesthetic compelling - though it is worth noting that Lovecraft's original work contains deeply problematic racial views, and the modern game is better understood as drawing from the broader Cthulhu Mythos tradition rather than endorsing Lovecraft's worldview.

Call of Cthulhu is less suited for players who want to feel powerful, enjoy tactical combat systems, or prefer optimising characters. Death and madness are not edge cases here - they are expected outcomes.

How does it differ from other systems?

Compared to Dungeons & Dragons, Call of Cthulhu is dramatically less combat-focused. Where D&D builds toward combat encounters, Call of Cthulhu builds toward revelations - and those revelations are rarely triumphant. Characters in D&D grow more powerful; investigators in Call of Cthulhu grow more fragile.

Compared to Blades in the Dark or other narrative-forward systems, Call of Cthulhu is more traditionally simulationist. It uses detailed skill lists, resource tracking, and a relatively rigid resolution system. It sits firmly in the classic RPG tradition, which is part of its appeal.

Where do you start?

Start with the free quickstart. Download it, read "The Haunting," and run it. It is a short, self-contained scenario that teaches the system through play without requiring anyone to read a full rulebook first.

When you are ready for the full game, have the Keeper read through the Keeper Rulebook's core chapters before session one. Players can come in cold if needed - the system is accessible enough that a brief character creation session is all it takes.

For external resources, the Miskatonic Repository on DriveThruRPG offers community-made scenarios. The YouTube channel of Chaosium has introductory videos, and recorded actual plays - particularly older episodes from the RPPR or Arc Dream communities - give a strong sense of tone and pacing.

Recommended products at Netherbook

The Call of Cthulhu Keeper Rulebook is your foundation. For groups starting fresh, the Call of Cthulhu Starter Set is the single best entry point - it includes everything needed for several sessions without additional purchases. The Investigator Handbook is a smart addition once your group is committed to the system. If your group wants more action and pulpy adventure, Pulp Cthulhu is an official supplement that adds a more heroic, two-fisted tone to the same rules framework.