Imperium Secundus was a short-lived human empire declared during the Horus Heresy, centred on Ultramar and ruled by three loyalist Primarchs. It existed because Guilliman thought Terra might already be lost.
Why it was declared
Erebus’s Ruinstorm tore a hole through warp travel across the Eastern Fringe. The Astronomican became useless, fleets couldn’t navigate, and the Imperium was effectively cut in half.
Roboute Guilliman had no word from Terra. Rather than assume the worst and do nothing, he put a contingency in motion: a successor Imperium that could carry on if the Throneworld had already fallen. He wasn’t sure Terra was gone, but he wasn’t willing to bet humanity on it.
How it came together
The Pharos on Sotha gave loyalists a way through the Ruinstorm. Warsmith Barabas Dantioch activated it, and refugees and scattered Astartes forces began arriving at Macragge.
Lion El’Jonson and the Dark Angels were among the first to reach Ultramar. Sanguinius and the Blood Angels came near the end, fresh from Signus Prime. In between, remnants of the Salamanders, Raven Guard, Iron Hands, White Scars, Imperial Fists and Space Wolves trickled in, along with the comatose body of Vulkan.
The triumvirate
Guilliman refused the crown. He’d seen what ambition had done to Horus and wouldn’t repeat it. He offered the role to the Lion, who also declined.
Sanguinius took it, reluctantly, as Imperator Regis. Guilliman served as Lord Warden and the Lion as Lord Protector, a title close to Warmaster. Three Primarchs, three jobs, one empire.
| Title | Holder | Role |
|---|---|---|
| Imperator Regis | Sanguinius | Head of state |
| Lord Warden | Roboute Guilliman | Civil administration |
| Lord Protector | Lion El’Jonson | Military command |
Cracks and collapse
The Battle of Sotha was the new empire’s first big test, and it held. But Konrad Curze was loose on Macragge, and his sabotage and killings drove a wedge between Guilliman and the Lion over what to do with him.
That rift never really healed. When the Ruinstorm finally broke and word from Terra got through, the whole project lost its reason to exist. The loyalists went back to the real Imperium, and Imperium Secundus was quietly set aside.
- Capital: Macragge
- Founded: 009.M31
- Peak size: roughly five hundred worlds
- Faith: Imperial Truth, no state religion
- Forces: Ultramarines, Blood Angels, Dark Angels, Ultramar Auxilia, loyalist Army and Mechanicum
Key facts
- Declared in 009.M31 during the Horus Heresy
- Centred on Macragge and the realm of Ultramar
- Reached roughly five hundred worlds at its height
- Ruled by a triumvirate: Sanguinius, Guilliman and the Lion
- Enforced the Imperial Truth, with no state religion
- Dissolved once the Ruinstorm broke and Terra was reachable again
FAQ
Who ruled Imperium Secundus?
Sanguinius was crowned Imperator Regis, with Roboute Guilliman as Lord Warden and Lion El’Jonson as Lord Protector. The three ruled together as a triumvirate.
Why didn’t Guilliman make himself emperor?
He saw Horus’s fall as a warning about personal ambition. He offered the throne to the Lion first, and only accepted a supporting role when Sanguinius took it.
How long did Imperium Secundus last?
Only a few years. It was declared in 009.M31 and dissolved once the Ruinstorm cleared and contact with Terra was restored.