Veins of the Earth

Veins of the Earth is a rules-lite OSR setting sourcebook for Lamentations of the Flame Princess. Compatible with any old-school system, it presents a terrifying Underdark where light is currency and survival is uncertain. Features 50+ original monsters, procedural cave generation, and revolutionary darkness mechanics. Dense, poetic, and utterly unique.

At-a-glance

Horror • 2-5 players • Needs GM • 3/5 complexity • High prep

Veins of the Earth

Veins of the Earth reimagines the Underdark as a place of genuine terror and wonder. Gone are the familiar drow cities and well-mapped caverns; in their place is a vast, three-dimensional nightmare of compressed deep time.

Theme and Setting

The Veins are older than human history, older than surface civilization—a place where paleolithic horrors still hunt, where the geometry of caves defies easy mapping, and where light itself becomes the most precious resource. Patrick Stuart's writing evokes the claustrophobia and awe of real caving expeditions, mixed with the surreal biology of deep-sea creatures and the cosmic indifference of Lovecraftian horror.

How Play Feels

The setting assumes that everything the surface world knows is a lie bounded by made-up borders. The true world extends endlessly below, bordered only by light above and fire below.

What Makes It Distinct

While primarily a setting book, Veins of the Earth includes substantial mechanical innovations. The encumbrance system uses a "significant item" approach that makes tracking gear manageable while maintaining meaningful choices.

Where It May Not Fit

You mainly want short standalone sessions with minimal carryover You want near-zero prep and immediate pickup play.

Decision guide

What this game is about

Key facts
Players
2-5 players + GM
Session
120-240 minutes
Prep
High
Play profile
Complexity
3/5
New GM Fit
2/5
Roleplay Focus
4/5
Combat Focus
3/5
Tactical Depth
1/5
Campaign Depth
4/5
Who it suits
Best for
Groups that want tension, danger, and unease to stay active at the tableGroups that want place, travel, and discovery to stay centralPlayers who enjoy danger, discovery, and player-driven problem-solving
Avoid if
You mainly want short standalone sessions with minimal carryoverYou want near-zero prep and immediate pickup playYou want low-tension or low-threat play

A strong fit for groups that want tension, danger, and unease to stay active at the table, with exploration-Driven helping define the experience.

Agent data

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

Open agent JSON