TTRPG Wiki

Compare tabletop RPG systems to find your next game

Basic Roleplaying

Universal Game Engine
The universal d100 system behind Call of Cthulhu and RuneQuest
View on DriveThruRPG →Affiliate link: we may earn a commission at no extra cost to you.
Universal
Skill-BasedModularSimulationGrittyRoleplay-HeavyInvestigationLow-FantasyClassless

Best For

GMs who want a modular, genre-agnostic percentile system they can tailor to any setting with optional rules for powers, combat, and more.

Core Mechanic

Roll d100 under your skill percentage to succeed. Critical success on 1/20th of skill value, fumble on 99–100. Opposed rolls compare results. Optional rules layer on complexity as desired.

Diced100
System FamilyBRP
PublisherChaosium Inc.
Year2023
ComplexityHow much there is to learn
Medium

The d100 core is simple: roll under a skill percentage, with crits and fumbles at the extremes. As a toolkit, its depth is optional and modular, layering combat and wounds, a powers subsystem, and professions onto the same percentile base. You add only the pieces your game needs.

AvailabilityHow you get the rules
  • Free to tryFull core rulesLegally free as an SRD, PDF, or official web rules
  • Get it nowAvailable nowFree to download or read online
RunnabilityWhat the book gives you to run it
  • ✓IndexFind any rule by page number
  • ✓GM guidanceA chapter on how to run the game
  • ✓Examples of playRules shown in action at the table
  • ✓Quick referenceCheat sheet or summary tables
  • ✓Cross-referencesRules point to each other by page

5 of 5 book tools found in the core book

Highlights

Highly modular: add or remove subsystems at will, intuitive percentile mechanic, unified system across any genre, skill-based progression through use, long design heritage

Considerations

Can feel generic without a specific setting, requires GM effort to select which optional rules to use, combat can be deadly and swingy

Rules license ORC

Similar systems

Added