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ESSER

Version 2.0
Genre-agnostic adventures you can explain in five minutes and finish in two hours
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universal
Rules-LightTheater of the MindOne-Shot FriendlyShort SessionsFast-PacedLow-PrepFreeform MagicCinematicClasslessRoll to Cast
✦ Indie Creator Submitted
Languages: English
Diced20
System FamilyStandalone
CostFree
LicenseProprietary
PublisherEspen Erlandsen
Year2026
Complexity Very Low
Accessibility Very High
Runnability Medium

Core Mechanic

Roll d20 + skill bonus + attribute bonus. A result of 1–9 fails with a complication, 10–14 succeeds at a cost, 15–19 fully succeeds, and 20+ succeeds with an epic effect.

Best For

Groups seeking a two-hour, genre-flexible one-shot where the same d20 engine handles action and conversation.

Highlights

The same d20 roll handles standard checks and direct contests, making transitions between scene types quick. Interface scales open-ended supernatural or technical effects by skill tier, letting one procedure cover magic and hacking. NPCs need a core bonus, Strikes, and an optional trait, so a GM can prepare threats with few statistics.

Considerations

No default setting is provided, so groups must supply a world for their adventure. Gear grants fictional permission rather than numeric bonuses, limiting equipment-based builds. Strikes reset after each adventure, so the track does not preserve mechanical attrition between adventures.

No verified publishing route found A bounded review of the complete official web rules found no stated third-party publishing route or explicit prohibition. Reviewed 2026-09-25 · Summary only, not legal advice. Check current terms before publishing.