Imperium Nihilus, also called the Dark Imperium, is the half of the Imperium that got cut off from Terra when the Great Rift tore across the galaxy at the end of the Thirteenth Black Crusade. It’s the darker, nastier side of the setting, and it’s where a lot of the current story is happening.
What it is and how it formed
When the Great Rift opened, it split the Imperium in two. The half still connected to Terra became the Imperium Sanctus. The half on the far side, mostly covering Segmentum Obscurus and a big chunk of Ultima Segmentum, became Imperium Nihilus.
The name fits. The Astronomican’s light is obscured there, so warp travel is a nightmare and astropathic messages often don’t get through. Before the Indomitus Crusade, the Imperium wasn’t even sure anyone over there was still alive.
What life is like in the Dark Imperium
It’s bad, and it’s bad in ways that make the Sanctus side look lucky. Chaos fleets and warbands operate almost unopposed. New daemon worlds have popped up, letting daemonic armies roam where they like.
Plenty of isolated worlds have effectively seceded, turning into petty kingdoms. Some of them fall under Chaos influence. There are rumours Abaddon is quietly steering some of these little empires, though it’s doubtful even he knows about all of them.
- The Astronomican is obscured, so navigation is unreliable.
- Astropathic communication is difficult or impossible.
- Chaos fleets and warbands raid with near-impunity.
- Many worlds believe they’re the last human outpost left.
Who’s in charge
Roboute Guilliman named Dante, Chapter Master of the Blood Angels, as Regent of Imperium Nihilus. Dante is working to turn Baal into the region’s acting capital.
Guilliman also made liberating the stranded worlds one of the stated goals of the Indomitus Crusade. Getting there is the hard part: crossing the Great Rift is described as difficult to nigh-impossible.
The Nachmund Gauntlet
A stable route across the Rift was eventually found. It’s called the Nachmund Gauntlet, and it’s now one of the most strategically important regions in the galaxy.
That single corridor is the main thread connecting the two halves of the Imperium, which makes it a target for basically everyone.
Notable worlds and regions
The Dark Imperium contains a lot of famous names from the setting, including several that have become flashpoints in recent lore.
| Worlds | Regions |
|---|---|
| Baal, Vigilus, Mordian, Valhalla, Cypra Mundi | Gothic Sector |
| Kar Duniash, Lucius, Sotha, Piscina, Dimmamar | Elara’s Veil |
| Attila, Elysium IX, Nemeton, Occludus, Khamun-Sen | Halo Stars, Ghoul Stars, Eastern Fringe |
Key facts
- Imperium Nihilus is also known as the Dark Imperium.
- It formed when the Great Rift split the Imperium after the Thirteenth Black Crusade.
- It covers much of Segmentum Obscurus and Ultima Segmentum.
- Dante of the Blood Angels serves as its Regent, based on Baal.
- The Nachmund Gauntlet is the one stable route across the Rift.
FAQ
What’s the difference between Imperium Nihilus and Imperium Sanctus?
They’re the two halves of the Imperium split by the Great Rift. Sanctus is the side still connected to Terra. Nihilus is the cut-off side, and it’s far worse off.
Who rules Imperium Nihilus?
Guilliman appointed Dante, Chapter Master of the Blood Angels, as its Regent. Dante is based on Baal, which he’s trying to make the region’s capital.
Can you travel between the two halves?
Barely. Crossing the Great Rift is described as difficult to nigh-impossible, though the Nachmund Gauntlet provides one stable route.