Rules reference
Combat in Call of Cthulhu 7th Edition
Turn flow, actions, and common combat rules. Call of Cthulhu 7th Edition is a horror investigation roleplaying game based on H.P. Lovecraft's Cthulhu Mythos. Players take on the roles of Investigators, ordinary people who uncover cosmic horrors beyond human comprehension. As you investigate mysteries, your character's Sanity slowly erodes, skills improve through use, and the line between reality and madness blurs.
Key points
Combat rules matter most when they keep scenes moving. This page focuses on decision points and the system’s core resolution loop.
- Percentile skill system: Roll d100, succeed if equal to or below skill rating
- 8 Characteristics: STR, CON, POW, DEX, APP, SIZ, INT, EDU
- Occupation system: Each occupation grants skill bonuses and Credit Rating range
- Sanity mechanics: Starts at 99-POW, decreases with Mythos encounters
- Skill improvement: Mark skills during play, improve after sessions
- Derived stats: HP, Sanity, MP, Build, Damage Bonus calculated from Characteristics
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.
- 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.
Instead of “I attack,” state the goal: “I push them back from the door” or “I buy time for the escape.” This makes outcomes clearer.
Once the winner is clear, wrap it. Don’t grind out the last 10% if it doesn’t change the story.
- Mistake: Unclear turns and slow decisions. Fix: State intent, pick one action, resolve fast, and move on.
- Mistake: Grinding after the outcome is obvious. Fix: End scenes early and narrate the final advantage.