|This article is about the surgical procedure; for the Audio Drama, see Butcher's Nails (Audio Book).
Bearing resemblance to a lobotomy, large amounts of nails trailed with cables which resemble dreadlocks were inserted through the skull and into the brain to amplify the anger and rage of the subject. The surgery was reserved for the slave-gladiators of Nuceria, amplifying their fierceness for the amusement of the masters of the planet. Angron was subject to the surgery, and later went on to repeat the procedure on his World Eaters. The Butcher's Nails that were implanted in the warriors of the World Eaters were primitive copies of the the originals implanted into Angron, although lacking in the fatal, degenerative effects of the originals. Early on, the implantation of the Butcher's Nails into World Eaters Legionaries under Gahlan Surlak had a 100% fatality rate, but Angron persisted in his demands to install the devices into his warriors. Eventually the process was perfected thanks to reverse-engineered Ghennan technology and Kharn was the first World Eater to survive the Nails. Unlike Angron's Nails which took the appearance of dreadlocks flowing from his skull, the mass-produced version resembled finer cables.
A form of Archaeotech, despite their brutal use the Butcher's Nails were surprisingly complex and sophisticated. None of the Emperor's best Tech-Priests, including the famed Vel-Kheredar, could remove the devices without killing Angron in the process, nor could they halt their slow destruction of the Primarch's brain.
At some point following the rediscovery of Angron, Arkhan Land was brought to a secret laboratory hidden in a dormant volcano in a tundra-based location on Terra to aid in the Emperor's investigation of Angron's crude augmetics as the Primarch lay unconscious. Land had previous experience with the device taking over Angron's body, having seen it when investigating the Hexarchion Vaults before he ordered them sealed due to the threat the items within presented to the Machine Cult. He told the Emperor that it was called a cruciamen, but the versions he saw were more crude. The Emperor explained that the implants were not His doing and that He believed they led to the Angron's instability. He also explained that they were recreated to remove the ability to enjoy anything but anger. When asked if the Emperor could remove it, He admitted He could, but the tendrils were deep in Angron's head and spine and he was missing his limbic lobe and insular cortex. The Butcher's Nails therefore replaced part of Angron's brain, allowing him to live.
"Butcher's Nails" was also an expression used among the gladiators of Nuceria for when, armed with no weapon except their bare hands, they would attack by stabbing their fingers at a victim's vulnerable points, such as the eyes or the meat of the throat.
- 1: Butcher's Nails (Audio Book) by Aaron Dembski-Bowden
- 2: After Desh'ea (Short Story) by Matthew Farrer
- 3: Betrayer (Novel) by Aaron Dembski-Bowden, Chapter 14
- 4: Master of Mankind (Novel) by Aaron Dembski-Bowden, Chapter Seven
- 5: Angron: Slave of Nuceria (Novel) Chapter 22