The Basalt Labyrinths of Chendiuria

A Subterranean World Beneath the Scorched Planet

1. OVERVIEW

Beneath Chendiuria’s blistering deserts and dead seas lies a network of natural volcanic caverns, tectonic fissures, and Burea of Colonies directed Research and Exploratory Corps abandoned test mining corridors stretching for hundreds of kilometers: The Basalt Labyrinths.

No official cartography exists. The basalt density is impenetrable to AI maps. No one—BuCol, corporate, or criminal—has accurate, up-to-date schematics.

The Labyrinths are older than the colonies. Older than the failed terraforming attempts. A geological nightmare that the first REC surveyors ignored until BuCol contracted exploratory miners disappeared in it.

It is hot, pitch-dark, and alive with unexpected things.

2. ENVIRONMENTAL CONDITIONS

• Heat: Ambient temperatures hover between 49°C and 73°C, depending on depth and geothermal proximity. Armor and exo-suits suffer accelerated sensor degradation.
• Atmosphere: Low oxygen, high mineral particulates. Sulfur traces common; toxic pockets present. Masks are mandatory even for lightly augmented individuals.
• Sound: Caverns carry long-distance echoes, but direction is impossible to judge. Acoustic hallucinations are common.
• Water: Almost none. What exists collects in geothermal runoff pools—boiling, acidic, high in dissolved silica and chloride salts, with minuscule amounts of potassium, lithium salts, boric acid, and fluorides.
• Light: Bioluminescence is rare, sporadic, and usually predatory.

3. HISTORY

The Labyrinths were discovered during early planetary exploitation when BuCol contracted drill teams attempted deep geothermal taps. Several shafts collapsed into open voids some the size of starport hangars.

In the first five decades of pre-colonial exploration:

• Twenty-seven drilling rigs were lost into the depths.
• Fourteen mining crews vanished without a trace.
• Official reports blame “geologic instability.” Chendiuria is geologically stable, with minimal geological activity.
• Unofficial logs blame “things moving in the walls.”

The Chendiurian government eventually sealed most surface entrances nearly 75 Standard Years after the colony was established. The criminal world later unsealed some.

Now the Labyrinths serve only three purposes:

• Illegal rare-earth mining (extremely dangerous and barely profitable, if at all, because Chendiuria is exceptionally mineral poor)
• Criminal hideouts / smuggler routes
• Places where people go when they don’t want to be found

4. THINGS THAT LURK THERE

Not all threats are biological.
Chendiuria’s underground is a mix of:

• Evolved fauna
• Rogue machines (rumored - no "official" proof exists of these supposed rogue machines)
• Abandoned experiments (also rumored)
• Criminal squatters
• Something else

5. BIOLOGICAL THREATS

Ironmouth Lashers

Carnivorous, cold-blooded reptile-arthropods roughly the size of a man’s thigh, armored in iron-hard silica-rich chitin that clangs when struck. Maw lined with serrated mineralized teeth. Lashers hunt by detecting vibration and heat. Lashers have an exceptional sense of smell, but the air currents in the Labyrinth are often too still for distance detection.

They are fast, silent, and capable of chewing through composite armor. Lasher drones are exceptionally territorial and fanatically defend their queen, her eggs and her nest.

Colonists believe they evolved from small desert scorpids that fell into the labyrinths millions of years ago. No proof exists.

Basalt Eels

Adult male eels are six meters long, limbless, carnivorous, cold-blooded reptiles living in geothermal runoff cracks. Temperature tolerance up to 85°C.

They have no eyes; they sense electromagnetic gradients via lateral organs. Eels live in large colonies with one queen, who is the largest eel in the colony, often exceeding ten meters. Eel queens do not leave their colony, instead relying on her harem to feed and care for her. Queens give birth to three to five live young, eating any that are weak.

Eels are not aggressive until they sense danger to their queen, sense a weakness, smell blood, or sense electrical discharge. Then they swarm. In an average swarm, there are seven to eight adult eels.

Gravelwraiths (possibly myth)

Eyewitness accounts describe tall, skeleton-thin creatures made of basalt dust and ceramic-metallic filaments.

No confirmed sightings by scientific teams exist.

But miners swear they:

• Appear only in groups of three
• Don’t leave footprints
• Cast no heat signature
• Mimic human movement

Some claim the Gravelwraiths are what’s left of early miners who died in collapses—nanite-corrupted echoes animated by Chendiuria’s magnetic flux patterns.

6. MACHINE THREATS

Abandoned Bore-Drones

Massive, twenty ton fusion powered automated, AI-controlled mining drones from the first geographic exploration and mapping.

The BuCol, REC, and first colonial wave left some of the various models of mining drones behind. On a planet so minerally poor, and a colony still deep in the red, lifting the old mining drones off the planet did not make fiscal sense. When some drones malfunctioned and slipped their human controllers, they retreated into the depths and ran corrupted programs.

Some capabilities include:

• Plasma and laser cutters
• Micro drilling mandibles
• Dense basalt sampling claws
• 3D-sonar mapping (unreliable)

Some drones have been underground for nearly a century, evolving new pathfinding routines. Many of those drones are not sane.

The various drones occasionally stalk intruders in their territory. Some drones are sane and may talk with explorers. Some of the better drone models may partake in simple goods exchanges, such as reactor mass or repairs traded for information.

Silt-Gnawer Microbots

Originally designed for geologic sampling. Nano-composite machines that break down mineral layers.

When abandoned in the labyrinth, they develop swarm tendencies. Researchers documented five swarms; many more are suspected.

Swarm contact causes:

• Superficial dermal stripping
• Armor pitting
• Communication interference
• Sensor blackouts

In dense concentration, they can blind a typical drone in seconds.

7. HUMANOID THREATS

The Thirteen Families of the Deep

Descendants of illegal prospectors who stayed underground rather than return to the surface.

Generations of:

• Low oxygen
• High radiation pockets
• Chronic mineral-laden diets
• Isolation
• Improvised medical care
• Inbreeding

Have produced communities with:

• Pale, grayish skin
• Enlarged eyes
• Stunted stature
• Enhanced low-light perception
• Strange dialects blending multiple planetary languages

They do not trust surface people and will kill to protect their territory. They consider surface people tasty and their livers a delicacy. The families frequently raid with the goal of returning with stolen female children and young women of childbearing age.

Basalt Cartel Deep Crews

Elite smuggler branch of the Basalt Cartel that move contraband through geothermal tunnels where scanners cannot reach.
Often armed with:

• 0ME machetes
• Various suppressed firearms, large bore shotguns especially
• Ceramic-composite lightweight power armor
• Null-signature visors

Deep Crews claim to have “underworld sovereignty” and enforce brutal laws. Killing outsiders is part of their operational doctrine. They are constantly at war with the Thirteen Families.

Pilgrims of the Core

A rogue techno-religious sect worshipping Chendiuria’s mantle as a living entity.

Their beliefs include:

• “The Planet hungers.”
• “Light is a lie told by the surface.”
• “Metal remembers its makers.”
• “Below is truth.”

They perform rituals in the deepest cavities. The Pilgrims are constantly at war with the Basalt Cartel (who view the Pilgrims as lunatic vermin) and the Thirteen Families. Human sacrifice is rumored. Their chants reportedly modulate seismic vibrations.

8. THE THING NO ONE CAN EXPLAIN

The Resonant Zone

A cavern so deep no confirmed maps exist. Exploration drones disappear. Ropes, wires, chains, etc. come back severed no matter how thick or strong. Sound recordings return corrupted, full of harmonic noise patterns that match no known fauna.

Some say the “zone” is:

• A living mineral structure
• An ancient xenobiological remnant (partial truth)
• A self-organizing nanite mass
• A hallucination triggered by magnetic flux (partial truth)

BuCol has four redacted files on it. One reads: “Seal at all costs.”

9. NOTABLE GEOGRAPHIC FEATURES

The Obsidian Cascade

A cliff face where molten rock once cooled mid-fall creating a formation that is several thousand meters wide and deep, but still not fully mapped.

Compared to the rock, a razor is less sharp, and obsidian from Old Terra is softer. Of the few people who have seen the Cascade, some say it looks like deadly frozen black rain. The slightest tremor causes millions of shards to fall. Some shards are the size and weight of an aircar.

The Boiling Spine

A serpentine geothermal fracture with periodic eruptions of steam hot enough to melt polymer reinforced boots.

The Quiet Cathedral

A cavern so acoustically perfect that a whisper carries for minutes. Miners and smugglers avoid it. The Pilgrims view it as sacred. The Thirteen Families use it for negotiations and executions.

The Carbon Bridge

A natural carbon-based arch spanning a drop so deep sensors cannot find the bottom. Surface gangs claim it’s cursed. Deep Crews use it as a checkpoint. The Pilgrims view it as sacred and drop offerings into the depths. Rumors persist that the Pilgrims drop human sacrifices from the bridge's highest point into the chasm.

The Mineral Mirror Lake

A still, reflective pool where the water is so heavy with dissolved silicates and metals it behaves like liquid chrome. Nothing lives in it. As far as anyone knows.

10. WHY PEOPLE GO DOWN THERE ANYWAY

• Rumor of rare minerals more valuable than gold (false)
• Smuggler routes invisible to satellite scans
• Cult sites for the truly unhinged
• Criminal refuge for those fleeing justice
• Scientific anomalies that shouldn’t exist on a dry planet
• Rumors of a pre-human structure buried deeper still

And some go for the stories. Most of them never return.