Vast Grimm

Vast Grimm is a rules‑lite sci‑fi horror game powered by Mörk Borg’s chassis. Classless, lethal, and fast to run, it focuses on grim survival, scavenging, and desperate missions against parasitic würms. Ideal for one‑shots or short campaigns where resource management and hard choices drive play.

At-a-glance

Dystopian • Needs GM • 4/5 complexity • One-shot friendly • Low prep

Genres:
Dystopian Horror Space-Western Science Fiction
Systems:
Old-School Renaissance (OSR)
Mechanics:
Rules Lite Survival
Themes:
Metal Bleak
Decision Tags:
Low Prep
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Vast Grimm

Rules draw from Mörk Borg’s ultra‑lean engine: ability saves instead of attack rolls, swingy damage, and equipment that matters. Character creation is fast and classless; gear and risks define play more than builds.

Theme and Setting

Tables, generators, and prompts speed up prep and make failure states interesting, not stalled. Vast Grimm leans hard into sci‑fi body horror: contamination, infestation, and desperate choices under pressure.

How Play Feels

The tone is loud and abrasive by design—layout and procedures reinforce urgency and danger. You’ll scavenge, jury‑rig, and burn resources to see another sunrise.

What Makes It Distinct

You want a very light rules load You want the system to stay almost invisible at the table. You want a very light rules load You want the system to stay almost invisible at the table.

Where It May Not Fit

You want a very light rules load You want the system to stay almost invisible at the table.

Decision guide

What this game is about

Key facts
Players
3-5 players + GM
Session
120-180 minutes
Prep
Low
Play profile
Complexity
4/5
New GM Fit
4/5
Roleplay Focus
4/5
Combat Focus
3/5
Tactical Depth
2/5
Campaign Depth
4/5
Who it suits
Best for
Tables that want quick onboarding and low mechanical dragPlayers who enjoy danger, discovery, and player-driven problem-solvingLong-form campaigns with room for the table to build momentum
Avoid if
You want a very light rules loadYou want the system to stay almost invisible at the tableYou want a much breezier tone than this game is built to support

A strong fit for groups that want quick onboarding and low mechanical drag, with rules Lite helping define the experience.

Agent data

Structured data and an explicit decision profile JSON document are available for remote agents.

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