Horus Heresy · atlas

Campaign · Ultramar · Segmentum Ultima · 007.M31 — 008.M31

Calth and the Shadow Crusade

The Word Bearers strike Calth as the heart of the XIII’s logistics. The Word Bearers’ ritual on Calth — and the massacre across the Five Hundred Worlds that follows it — gives birth to the Ruinstorm; the poisoned Veridia is a weapon against the XIII, not the sacrifice from which the storm was born. Angron and Lorgar scorch Ultramar; on Nuceria Angron ascends to Khorne.

Outcome A Pyrrhic traitor victory: Ultramar is wounded, the Storm is born, but Guilliman lives, the XII/XVII have bled themselves white, and the XIII is not destroyed.

Commanders

Loyalists

Commanders

Traitors

Commanders

Theatre
Ultramar · Segmentum Ultima
Period
007.M31 — 008.M31
Legions
Systems

Analysis

This is not one battle but a two-beat blow against the east. Beat one — Calth (007.M31): the XVII arrives as an “ally” at the muster, knocks out the orbital defences, poisons Guilliman and drives the Ultramarines underground. The aim is not to seize the shipyards but to turn the system into an altar — the Word Bearers’ ritual; the poisoned Veridia lashes the XIII with flares, and the Ruinstorm slices the galaxy. Beat two — the Shadow Crusade: the XII and XVII go not towards Terra but through the worlds of Ultramar (Armatura, Percepton, Nuceria). Horus agrees: as long as Guilliman lives and the east is tied down, Terra will not receive 250 thousand of the XIII. Nuceria (008.M31) is the theological finale: the first primarch ascended by Khorne. The price is that the XII ceases to be an army that can be posted to stand watch in the siege. Ultramar survives as an idea (Secundus), not as an untouched empire.

Order of battle

Calth: a considerable share of the XIII against the strike forces of the XVII (Kor Phaeron, Erebus). Titans on both sides (Ithraca). Shadow Crusade: ~70 thousand of the XII with Angron plus contingents of the XVII against the leaders and worlds of Ultramar, not gathered into a single fist.

Turning points

  1. 007.M31 Betrayal at Calth — Battle of Calth

    The orbit goes dark, Guilliman is nearly killed by Kor Phaeron. The XIII Legion goes underground.

  2. 007.M31 The Birth of the Ruinstorm — Birth of the Ruinstorm

    A ritual at Calth; Veridia is a weapon, not a sacrifice. The east is cut off.

  3. 007.M31 Armatura — Battle of Armatura

    A model fortress world of Ultramar is ground down. The campaign becomes a scorching, not a raid.

  4. 008.M31 The Ascension of Angron — Battle of Nuceria · ascension of Angron

    The first primarch ascended by Khorne. The XII Legion is theologically complete and militarily broken.

Events of the campaign

  1. 007.M31 Battle of Calth Pyrrhic loyalist victory

    Having gathered the Ultramarines at Calth under the pretext of a campaign against the orks of Ghaslakh, the Word Bearers of Kor Phaeron and Erebus struck without warning and turned Calth’s orbital…

  2. 007.M31 Betrayal at Ithraca Pyrrhic traitor victory

    As part of the Calth betrayal, the Word Bearers, Legio Suturvora (the “Fire Masters”) and the Ordo Reductor fell upon the loyalist Taghmata Xerxes of the forge world of Accatran and a stranded…

  3. 007.M31 Birth of the Ruinstorm Atrocity

    Erebus’s ritual on the surface of Calth and the slaughter of Ultramar gave birth to the Ruinstorm — a gigantic warp storm centred on Ultramar, cleaving the galaxy in two.

  4. 007.M31 Battle of Armatura Traitor victory

    The World Eaters and Word Bearers stormed Armatura — the great military-college world of Ultramar, where aspirants were trained.

  5. 007.M31 Shadow Crusade Inconclusive

    While Kor Phaeron struck at Calth, Lorgar and Angron led the Word Bearers and World Eaters against the Five Hundred Worlds of Ultramar, burning world after world.

  6. 008.M31 Battle of Nuceria · ascension of Angron Traitor victory

    The climax of the Shadow Crusade on Angron’s home world of Nuceria: Guilliman fought Lorgar and Angron in the city of Meahor and was overthrown, saved only by the intervention of the Ultramarines…

Significance

Cuts the galaxy in two and creates the conditions for Imperium Secundus. For years Terra is left without the eastern Legions.

How to look in the atlas
  • Time slider 7.0…8.4; in the “Legions” rail keep the XIII and XVII: you will see that the blow was aimed not at the fleet but at Ultramar’s logistics.
  • The Shadow Crusade routes at 007.M31 will show that the XII and XVII are NOT heading for Terra.

Show on the map

Open in the atlas

Sources

  1. Know No Fear (D. Abnett)
  2. Betrayer (A. Dembski-Bowden)
  3. Forge World Black Book V: Tempest
Open in the atlas

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