AI Dungeon Master
for OSR games.

The OSR design philosophy

Old-School Renaissance (OSR) games reject the idea that the rules should solve every problem. When your thief is cornered in a trapped corridor, an OSR game says: make a ruling. Roll the die. Live with the consequences. The rules are a scaffold — not a crutch.

Mechanically, OSR games tend toward high lethality, d20 roll-under checks, save-or-die scenarios, and inventory slots instead of encumbrance math. Characters level through gold and discovery, not XP from combat. The genre descends directly from early D&D — B/X, Original, AD&D — and has evolved into a thriving indie space that prizes mechanical elegance over mechanical depth.

If you have ever stared at a 400-page rulebook and wondered why a skill check takes three paragraphs, OSR is the antidote.

Games you can playtest with SagaForge

The OSR umbrella covers some of the most-played indie games in tabletop history:

• Mörk Borg — fatalistic, neon-drenched doom metal for the dungeon.
• Mothership 1e — sci-fi horror with a panic mechanic and zero padding.
• Knave 2e — classless, slot-encumbered, brutally simple.
• Cairn — five stats. a single page of rules. go.
• Mausritter — isometric mouse dungeon-crawling, powered by Into the Odd.
• Electric Bastionland — procedural, weird, almost no alignment or classes.
• Into the Odd — copper-scale HP, three stats, your first hit kills most characters.
• Whitehall — torch-and-doorway hex exploration, designed for pick-up play.

All share the same DNA: rulings over rules, death as a real possibility, and exploration as the primary activity.

You do not need a table full of players to find out if your rules work

Testing an OSR game is different from testing a trad game. Players expect lethality — they want to feel the danger. But edge cases appear fast: what happens when the party splits inside a trap corridor at midnight with no light? What does a morale check look like when the enemy leader dies?

Rounding up players for a one-shot OSR test is a pain. Most of your playtest pool will not survive the rules learning curve before the session gets interesting. You need something that can run a session at 2am, enforce your save-or-die rulings, and give you a clean report afterward.

SagaForge does exactly that. Paste your OSR rules — or pick a preset — and get a 10-action session with designer notes in 90 seconds. You will know inside an hour whether your death spiral works, your dungeon is too lethal, or your inventory system creates the right friction.