Mythras Variants

Built around Mythras, with first-class support for its sibling games and house rules.

Mythras Core

The full Mythras experience: rolled characteristics, hit locations, action points, combat styles with special effects, folk magic, sorcery, mysticism, and passions. Every system from the core rulebook is modeled the way the book expects.

Mythras Imperative

The free, streamlined version of Mythras for one-shots and new players. Same skill-based d100 engine, lighter character creation, and fewer moving parts — ideal for getting a table rolling in an afternoon.

Casus Mus

The Mythras-derived game of mouse adventurers. Different scale, different tone, but the same underlying d100 system — demonstrating how far the ruleset layer can flex.

Configurable Strategies

Rulesets pick the right strategy for each subsystem: characteristic generation (roll vs point buy), hit points (locations vs single pool), armor (blocks vs reduces damage), combat (standard vs simplified), and action points (variable vs fixed). That is what lets Mythras Core, Imperative, and Casus Mus all share one engine.

YAML-Driven Data

Species, cultures, careers, skills, combat styles, weapons, and spells live in structured YAML files. Add a new culture, tweak a career's bonus skills, or build an entire homebrew setting without touching the application code.

Formula System

Skills and attributes use derivation formulas like STR+DEX that resolve against character characteristics. The formula evaluator handles arithmetic, functions (ceil, floor, round, avg), and lookup table references — the same way the Mythras rulebook expresses derived stats.