|Outcome||World Eaters victory|
Butcher's Nails begin widespread use within the World Eaters
|World Eaters||Ghennans||World Eaters Rebels|
| Primarch Angron
Apothecary Gahlan Surlak
|Unknown|| Centurion Mago(KIA)|
|Several thousand World Eaters|| ~1,000 true Ghennans
Billions of artificial humanoids
|Several hundred World Eaters|
| Initially heavy
|All annihilated||Most surrendered|
The Ghenna Massacre, also known as the Second Compliance of Ghenna, was a campaign during the Great Crusade.
Ghenna had initially not resisted Imperial compliance, but several years after its supposed occupation all contact with the planet stopped. The World Eaters under their Primarch Angron were dispatched to investigate, and negotiations quickly broken down with the Ghennans when it was discovered that they had modified their own forms and were using an apparent form of Abominable Intelligence. Ghenna was sanctioned by the Imperium for conquest, and as was tradition the Primarch demanded that the world be subjugated within 31 hours (a standard Nucerian day) on penalty of decimation should they fail. The prospect of 1 of every 10 World Eaters being executed for their failure created a hastily and poorly executed landing on the planet under the Centurion Mago, who was desperate to avoid yet another massacre of his own Legion brothers.[2a]
However upon reaching Ghenna's surface they encountered no standard resistance, instead the entire planetary populace consisted of synthetic "Simulacrum" in the form of Humans. These simple constructs simply used their weight of numbers to swarm the World Eaters, bringing the warriors down one by one regardless of how many the Astartes were able to slay. The hasty nature of the invasion meant there was little in the war of orbital bombardment or heavy armor or artillery, and despite Mago's best efforts for a time it seemed the World Eaters would be overrun. However heavy support finally was able to land, and once securing a landing zone Mago organized a counterattack that finally broke through the untold billions of Ghennan Simulacrum. However just as they were able to break into the main Ghennan city, Angron's 31-hour timer expired and the Legion were forced to journey back aboard the Conqueror.[2b]
Aboard the Conqueror, Angron ordered yet another round of decimation but Captain Mago refused. This amused the Primarch, who instead ordered Mago to personally murder the first World Eater to die. When Mago again refused, Angron was sent into a blind rage that saw him murder swathes of his own sons. Only the World Eaters Librarians under Vorias were able to eventually subdue Angron by putting him into an unconscious state, though several died in the process. Angron however would not wake from his slumber, and a crisis soon erupted within the Legion over what should be done.[2c] It was in this instability that the Apothecary Gahlan Surlak announced that thanks to reverse-engineering Ghennan technology, he now had a stable method of installing the Butcher's Nails throughout the Legion as Angron had consistently ordered. Mago was horrified by the prospect of a Legion enraged by the Nails, and began to plot with other old Terran War Hound veterans.[2d]
Ultimately, Mago's plan to destroy Surlak's Ghennan technology within his laboratory failed thanks to the Apothecaries defensive countermeasures, and it was revealed that Kharn had since become the first World Eater to be successfully imbued with the Butcher's Nails. With Mago plotting his next move, Kharn and Surlak immediately installed the Nails into 1,000 more World Eaters and alongside Angron once again re-invaded the surface of Ghenna. This time the World Eaters massacred all they came across, and thanks to Surlak localizing the Ghennan command signal were able to find the shrivled form of the Ghennans in their life-pods. In truth there were only a little over a thousand true Ghennans, with each mentally controlling thousands of simulacrum. The Ghennans pleaded to be left alone and spared, but Kharn announced that the galaxy belonged to the Imperium and massacred them all.[2e]
After the World Eaters razed the Ghennan capital, they were confronted by Mago and his loyalist World Eaters, pleading with Angron and Kharn to halt their madness. A battle broke out, during which Kharn personally slew Mago in a duel. The surviving insurgents submitted themselves before Angron, and with the Legion again unified the World Eaters scoured the surface of Ghenna, leaving no structure intact and none alive in a single night of incredible bloodshed.[2f] The psychic screams of the dying were audible by Astropaths across half the Sector.
In the aftermath of the massacre the Leman Russ and the Space Wolves confronted Angron and his World Eaters to demand an end to the Butcher's Nails implementation within the World Eaters. This eventually led to the infamous Night of the Wolf.
- 1: The Horus Heresy Book One — pg. 88
- 2: Angron: Slave of Nuceria (Novel)