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Belly of the Beast

Core Rulebook
Cruel scavengers picking through the digestive guts of a world-eating monster that swallowed civilization
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post-apocalyptichorror
SurvivalGrimdarkGrittyHorrorPlayer-Only RollsTheater of the MindResource ManagementInventory ManagementRoleplay-HeavyAtmosphericSandboxFiction-FirstFaction PlayClasslessSkill-BasedWeirdGM-Friendly
Languages: English
Diced6 dice pool
System FamilyEthos Engine
Cost$
LicenseProprietary
PublisherSigil Stone Publishing
Year2016
Complexity Medium
Accessibility Medium
Runnability High

Core Mechanic

Roll 1 base d6 plus up to 5 Instinct Dice spent from a refillable pool plus any Advantage Dice, capped at 10 total. Each die is a success on a face value set by your relevant Skill Rank — Rotten (6), Acceptable (5+), Capable (4+), Brilliant (3+). Tasks have a Difficulty (successes needed), Severity (how much failure hurts), and optional Threshold (successes removed before counting). Players roll for everything; the GM never rolls. Spent Instinct Dice are gone until earned back by acting in line with your two Instincts.

Best For

Groups who want grim survival horror in a confined weird-fiction setting where character Instincts and a scavenging mission cycle — not heroic combat — drive every session, and who are comfortable with a GM who never rolls and tunes threats by feel.

Highlights

Instinct Dice tie character drives directly to dice pool depth — acting on your two Instincts earns dice you spend to survive future rolls, so leaning into your character's flaws is how you stay mechanically competent. Tasks have three independent dials — Difficulty, Severity, and Threshold — letting the GM build a D1/S4/T0 assassin or a D5/S1/T2 vault door that feel mechanically distinct without an enemy stat block. Succumb and Transcend let any player auto-resolve a Task or Scene by embracing or permanently renouncing an Instinct — Succumb leaves the character Ashamed and unable to Advance until they atone, while Transcend removes that Instinct and its dice income from the sheet forever.

Considerations

Players roll for everything and the GM never rolls, so every Enemy, Hazard, and Sickness is a Difficulty, Severity, and Threshold the GM sets by feel during play rather than reading from a stat block. Combat uses abstract Hand/Arm/Reach/Near/Far ranges with no grid, no movement tracking, and no initiative — the GM calls turn order from the fiction. Setting material includes normalized slavery, frenzy-mad cannibals, and an in-fiction gender framing where women are treated as more 'precious' than men due to reproduction — the book flags the last point in a sidebar and suggests GMs skip it if uncomfortable.