The Mordian World is a tidally locked Imperial hive world where half the planet never sees the sun. It’s famous as the home of the Mordian Iron Guard, one of the most disciplined regiments in the Astra Militarum, and it’s been a Chaos battleground since the Great Rift tore the galaxy apart.
What the mordian world actually is
Mordian is a hive world in the Segmentum Obscurus, sitting in the Stygius Sector. Its rotation is locked to its orbit, so one hemisphere bakes under a permanent sun while the other stays in endless night. All life clings to the dark side, which is why it’s nicknamed the World of Eternal Night.
Hundreds of millions of people live on a land surface about a tenth the size of Earth. The hive cities rise as pyramidal, multi-level towers that look like mountains reaching for space. The ruling Tetrarchy rations every scrap of resources, and the Iron Guard is basically the only thing keeping order from collapsing into total anarchy.
- Class: Hive World
- Segmentum: Obscurus, Stygius Sector
- Nickname: World of Eternal Night
- Government: the Tetrarchy
- Home regiment: Mordian Iron Guard
The Iron Guard and why Mordian matters
Mordian’s real export is soldiers. The Iron Guard are known for rigid discipline, iron-hard drill, and parade-ground precision that somehow survives contact with the enemy. They’re the regiment the Imperium calls when it needs a line to hold no matter what.
The planet itself matters because it’s a fortress world in a strategic sector. It’s also a pressure cooker: scarce resources, cramped hives, and a strict government breed constant discontent. That tension is part of what makes Mordian’s regiments so tough, and so necessary.
Chaos invasion and the Battle of Mordian
Mordian’s biggest early crisis came from a Chaos cultist conspiracy. A summoning spell opened the way for ships from the Eye of Terror, dropping Chaos Marines from the sky while daemons materialized in the streets. The Iron Guard eventually won the Battle of Mordian, but it was a close-run thing.
The Dark Imperium and the Stygius war
After Roboute Guilliman returned and the Great Rift split the galaxy, Mordian was one of the worlds stranded in the Dark Imperium. The Thousand Sons and their cultists besieged it during the Invasion of the Stygius Sector. The Stygius Crusade broke the siege, but it couldn’t beat Tzeentch’s forces and had to pull back.
Mordian held on thanks to the Iron Hands and their successor chapters. Since then it’s become a free-for-all: the Thousand Sons sorcerer Khethos Vorsch, an agent of Ahriman called The Vessel, the Great Harlequin Rillietann, and Necron overlords Serevakh and Trazyn all have a stake in the fight. Vorsch eventually shattered the Webway above Mordian, dragging the realm of Shaa-Dom over the world and throwing everything into chaos.
| Event | What happened |
|---|---|
| Battle of Mordian | Chaos cultists summoned an invasion; the Iron Guard won |
| Dark Imperium | Mordian stranded after the Great Rift opened |
| Invasion of the Stygius Sector | Thousand Sons and cultists besieged the world |
| Stygius Crusade | Broke the siege but retreated from the sector |
| Webway shattering | Khethos Vorsch brought Shaa-Dom over Mordian |
Key facts
- Mordian is a tidally locked hive world in the Segmentum Obscurus, Stygius Sector.
- It’s ruled by the Tetrarchy and home to the Mordian Iron Guard.
- Life exists only on the night side, on a land surface about a tenth of Earth’s size.
- The Iron Guard defeated a Chaos invasion in the Battle of Mordian.
- Mordian was stranded in the Dark Imperium after the Great Rift opened.
- Khethos Vorsch shattered the Webway above Mordian, bringing Shaa-Dom over the world.
FAQ
Why is Mordian called the World of Eternal Night?
Because it’s tidally locked, one side always faces its sun and the other never does. All life exists on the dark hemisphere, so the planet is permanently night for its inhabitants.
What regiments come from Mordian?
The Mordian Iron Guard. They’re an Astra Militarum regiment famous for strict discipline and unbreakable firing lines.
Is Mordian still held by the Imperium?
Yes, but barely. The Iron Hands and their successors helped keep it in Imperial hands after the Stygius Crusade retreated, though multiple factions are now fighting over it.