Coriolis: The Great Dark — Expeditions into the ruins of a dead civilization

"The star portals are dead. Explore or perish."

Diced6 pool (Base + Gear dice)

Players1–5

Prep~45 min

Foundry VTTOfficial

Complexity

What is this system

A standalone sequel to Coriolis: The Third Horizon, but a very different game. Instead of trade and intrigue between the stars, you run expeditions into the ruins of the vanished Builders, inspired by 19th-century expeditions, deep-sea diving and pulp archaeology. A reworked Year Zero Engine, three damage tracks for body, mind and heart, and a mechanical bird you really don't want to delve without.

Is it for your table?

Pick it if

you want expeditions into alien ruins, delve by delve, as supplies run low
your players would rather discover the setting in play than read lore first
you might play solo or with a tiny crew — it supports 1–5 players

Skip it if

you want the trade, faction politics and star-hopping of the original Coriolis
your group dislikes tracking supply, gear wear and three separate damage tracks
you want fast action rather than slow, careful delves into ruins

Setting

After a long voyage, the refugee fleet of the Diaspora settled in the lone Jumuah system and turned its ships into Ship City on an asteroid. The Machinists, Gardeners and Navigators guilds keep the colony alive, while Explorers ride the few Greatships down the Slipstream to other stars. The Builders' ruins hold artifacts — and the Blight, an icy plague that twists bodies and minds. The lore is meant to be discovered in play, not read up on beforehand.

What it looks like at the table

Depth marker seven. The Scout sent the bird ahead, and it came back with bad news: Blight Level 2 behind the ancient door. You work the lock: Agility 3 plus the *Ruin Delver* talent at 1 gives 4 Base Dice, plus 1 Gear Die from your tools. You roll 2, 3, 4, 5 and a 4 — no sixes. You push: reroll everything that isn't a 6 or a 1. A six — the door gives way! But a 1 on a Base Die costs you 1 Hope, and a 1 on the Gear Die knocks your tools' Gear Bonus down by 1. Beyond the door the Blight hits your Heart for 2; your suit's Blight Protection is 2, so you roll two Gear Dice and get 6 and 3. Each six cancels a point, and you lose only 1 Heart.

Playstyle

Exploration Mystery Survival Space

Key mechanics

Base Dice and Gear Dice

Attribute plus talent level is how many Base d6s you roll, plus Gear Dice from the right equipment. You need at least one six; every extra six improves the result.

Push at the cost of Hope

Failed? You can push once, rerolling every die that isn't a six or a one. But each 1 on your Base Dice when you push drains Hope, and 1s on Gear Dice wear your equipment down.

Health, Hope and Heart

Three tracks instead of one: damage hits Health, despair hits Hope, and the Blight eats away at Heart. Run out of Heart and you suffer a Blight manifestation — from glowing skin and creeping vines to far worse.

The bird and the delve

Every crew gets a Garuda bird, an electromechanical automaton from the Builders' era. It scouts the Blight ahead and spends Energy on uncanny abilities. Delves go marker by marker of Depth, and your Supply dwindles with each one.

What people say

Coriolis: The Great Dark does a good job of presenting an original twist on the space opera genre.— Aaron Marks, Cannibal Halfling Gaming

Art & materials