The Eridanos Star System is built on the SRD, which contains rules for play. The rest of the rules under here relate to character creation and situations unique to playing space horror campaigns.

Eridanos Star System is a game with fast character generation, 6 character classes, customizable advancement, spaceships, and the horrors of staring into the void.

Version 0.1.1

Franco A. Alvarado / Root Devil

This game is heavily based on Monolith and Meteor in addition to a variety of other sources listed in the Bibliography.

Eridanos System Open Table Campaign

Pitch for the Eridanos System local open table game.



This campaign starts with Gradient Descent. Gradient Descent is a space horror module set in an AI factory called CLOUDBANK Synthetics Production Facility, nicknamed THE DEEP. It can be explored multiple times in separate excursions for different objectives.


The adventurers are trying to get in and get out after achieving their goals. It is possible to die if you are not careful but new characters can be generated quickly.


The setting is a little grim but we don’t need to be. It is mostly meant to be scary as heck.

Subject Matter

As a content warning, since this is a space horror module, there is body horror, violence, psychological distress, and trauma featured, all of which can be veiled. There is also harm to android children, which can be removed.

The module includes a mechanic called the bends that may result in players losing control of their characters. It builds up in a gradual way and won’t happen all of the sudden; however, if that is not a thing that sounds fun to you, we can take that out too.


Each session that involves a brand-new crew should start with the crew traveling to THE DEEP and should end with them exiting to a safe location outside THE DEEP (either the Bell, one of the ships blockading THE DEEP, or their own ship).

Any crew that ends their session inside THE DEEP leaves their characters there. They awaken next session with a gap in memory, lost somewhere in the depths of the factory.

Setting: Eridanos System

A star system settled by humanity escaping the dying Solar System three hundred years ago on one thousand Generation Arks. Only 236 ships made it.

Starting from the zones closest to Eridanos Star:

  1. Near Zone: Hot rocky planets
  2. Habitable Zone: Lush planets
  3. Gishra Ring: Colder planets, covered in water, occupied by the Gishra
  4. Far Zone: Contains nebulas, gas giants, mineral-rich asteroids. Exploited by Corporations.
  5. Stex Rim/Corpospace: Exploited by Corporations. Many cold mineral rich planets and moons with little habitability. Space stations and outposts. This is where the Deep is. Also home to the Stex.
  6. Outer Rim: Cold. Dark. Dead Generation Arks populate the space. Vugruin Outposts. Ice clouds.

Sublight travel is most common. FTL travel is made safer by utilizing Anchor Points across the system. Otherwise, it is costly and potentially risky.

Significant Species

Aliens are not playable species right now.

  • Vugruin: Vugruin Space is located outside of the Eridanos System and consists of multiple star systems. Early in human settlement of the Eridanos System, Vugruin would sometimes make contact. Vugruin did not consider humans sentient and would engage in “pulling apart” ships, stations, and even humans. It is rumored that many Generation Arks did not make it to Eridanos because they were destroyed by curious Vugruin. Vugruin technology far outpaces that of humans. Two hundred years ago the human governments worked together to convince the Vugruin to sign a treaty stating that humans were a “significant species.” Corporations and successor governments have maintained this treaty, which if violated (by any human attacking Vugruin), would render it null and void. Vugruin do trade and maintain diplomatic relations with human representatives but since they are physically incapable of speaking human languages, they send Translators bred specifically for that purpose. They resemble humans and are grown from human body parts (and do not always look quite right).
  • Gishra: A fish-like people from the Gishra Ring. They are isolationist and signed onto the Vugruin-Human treaty to protect themselves. They find off-world travel distressing and do exploration via drones. Their technology is at the human level. Some humans have been integrated into Gishra society (biologically modified to grow gills). Gishra reproductive strategy is to produce several offspring, very few of which survive to adulthood. Parents are known to eat weaker offspring.
  • Stex: Serpent-shaped creatures covered in fur that communicate in sibilants hisses. Signed onto the treaty to protect themselves.

Player Instructions

  1. Crew your vessel
  2. Meet your diver
  3. Generate your stats
  4. Gear up

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