Call of Cthulhu 7th Edition GM resources

Horror investigation RPG

Call of Cthulhu 7th Edition is investigative cosmic horror. Percentile rolls under skill, pushed rolls, Sanity and Luck tracked live.

Call of Cthulhu uses percentile skills: roll d100 and succeed if you roll at or under your skill. Difficulty often shifts the threshold (Regular/Hard/Extreme) and Sanity loss is a core pressure loop. The roll flow has 3 steps: Pick the relevant skill (e.g., Spot Hidden, Library Use). Roll d100 and compare to your skill rating (and difficulty threshold). Apply consequences: information gained, complications, or Sanity loss when appropriate.

This page collects resources for running Call of Cthulhu 7th Edition. It links to 6 GM topics written for this game, starting with the session zero guide.

How to use this page

1. Start with session zero, then pick the topic that matches your next session. Each topic is short enough to read while prepping a Call of Cthulhu 7th Edition scene.
2. Open the Call of Cthulhu 7e dice roller when a rule asks for a roll, so the result follows the same mechanic described above.
3. Track what changes on your Call of Cthulhu 7e character sheet, which supports 3 creation modes, so the next session starts from the current state.
4. Move to a sibling page when the question changes: quickstart, rules reference, glossary, or advancement guide. Each one is built from the same Call of Cthulhu 7e data, so terms and numbers match across pages.
5. Return to the Call of Cthulhu 7th Edition guide for the full overview, including character creation and every tool for this game.

Nothing on this page replaces the published Call of Cthulhu 7th Edition rulebook. It is a working reference for the table: short summaries of the 6 GM topics listed here, plus links to the tools that act on them.