The Shadow Crusade was a campaign of the Horus Heresy. Making up the second theater of the Eastern Fringe campaign of the Heresy alongside the Calth Front, it was a campaign by the Word Bearers and World Eaters against the 500 worlds of Ultramar.
During the Word Bearers offensive against the Ultramarines in the Battle of Calth, Lorgar led another contingent of Word Bearers in conjunction with Angron and his World Eaters targeting the rest of Ultramar. The ultimate goal of Lorgar was to create a massive Warp storm known as the Ruinstorm, which would create an impenetrable veil around Ultramar and the eastern half of the Galaxy, cutting off the largest of the Emperor's Legions from Terra. The Ruinstorm had first been summoned by Erebus during the Battle of Calth, but to mature it fully Lorgar needed to unleash a campaign of bloodshed and misery.
The Word Bearers and World Eaters launched a far bloodier and reckless offensive on their way across the eastern Galaxy, rampaging across the 500 worlds of Ultramar. Initially the two legions were on tense terms, as Angron delayed the advance by insisting on the butchering of entire worlds of little strategic value. The tensions between Angron and Lorgar boiled over to a standoff that was only interrupted by an attack by Dark Eldar.
One of the most pitched of the campaign was the Battle of Armatura, where the traitor fleet led by two gigantic Furious Abyss-class battleships smashed through massive Ultramarine defenses. During the butchery Lorgar realized that Angron's fury was consuming him as the Butcher's Nails could not handle a Primarch's brain. Lorgar, wishing Angron be elevated to serve the Dark Gods, decided to journey to his homeworld of Nuceria to find the secrets of the Butcher's Nails. While Lorgar led a small force to Angron's world, the rest of the traitor fleet splintered into many small parties which brought destruction upon every Ultramar world they encountered. Talassar and Percepton are other worlds that are known to have been attacked by the traitors.
When the two Primarchs arrived at Nuceria however they discovered that the slave-lords of the world had massacred Angron's comrades and told the population that he had fled during their last stand. Infuriated, Angron ordered that the World Eaters and Word Bearers purge Nuceria of its population. During the ensuing battle, the Ultramarines led by Guilliman arrived, determined to exact vengeance on the traitors for the Battle of Calth. The three immensely powerful but vastly outnumbered traitor Battleships (Conqueror, Fidelitas Lex, and Trisagion) faced a rag-tag Ultramarines fleet of 40 smaller vessels. The ensuing battle in space was nearly even, in large part thanks to the vast power of the Trisagion. However due to their numbers Ultramarines vessels were able to move past the traitor blockade and land forces on Nuceria. They also managed to bring down the Fidelias Lex, losing twelve ships in the process.
On the ground, loyalist and traitor astartes and Titans began to engage each other in pitched combat. Lorgar went on to duel Guilliman himself during the battle, and the two were largely evenly matched. However Angron then arrived, and defeated the Primarch in a furious rage. But while Guilliman managed to escape thanks to an intervention by nearby Ultramarines, this was precisely what Lorgar had wanted and the Word Bearers Primarch began a Khornate ritual. Using Angron's rage as a conduit, Lorgar channeled the power of Khorne and surged the Red Angel with the powers of Chaos. Angron was transformed into a hulking, even more bloodthirsty avatar of violence and rage that had overcome the debilitating effects of the Butcher's Nails. With his brother empowered and the Ruinstorm now at its crescendo, the traitor fleet withdrew.
Thanks to the mass carnage and pain unleashed, the Word Bearers were successful in strengthening the Ruinstorm, creating havoc across Ultima Segmentum and effectively dividing the Imperium in half. Those loyalist legions now isolated from Terra; not only the Ultramarines but also Dark Angels and Blood Angels, were forced to muster at Macragge where Guilliman eventually formed Imperium Secundus. The Dark Angels continued to purge traitor forces from Ultramar during the hunt for Konrad Curze, most notably during the Battle of Zepath.
Even after Terra became the focus of the war and the Primarchs left to wage battle elsewhere, fighting continued to rage in Ultramar from remnants of the Shadow Crusade. These included the Butcher Fleets of the World Eaters and the Argolian Massacres of the Word Bearers.
Notable Individual Actions of the Shadow Crusade
- The Battle of Armatura
- The purging of Nuceria
- The Percepton Campaign
- The Battle of Zepath
- The Crusade of Iron
- Battle of Anuari
- Argolian Massacres
- 1: Betrayer (Novel), [Needs Citation]
- 2: Vengeful Spirit (Novel), [Needs Citation]
- 3: The Unremembered Empire (Novel), [Needs Citation]
- 4: Butcher's Nails (Audiobook)
- 5: The Purge (Novella), Chapter 1
- 6: Angels of Caliban (Novel), Chapters 3-6
- 7: The Laurel of Defiance (Short Story)
- 8: The Horus Heresy Book Five - Tempest, pg. 81
- 9: Warhammer Community: Shadow and Iron: Crusades of Vengeance (posted February 5 2020) (last accessed 2/5/2020)
- 10: Adeptus Titanicus: Shadow and Iron, pgs. 7-10
- 11: White Dwarf 478, pgs. 104-105