Devourers

The Devourers were the premier cadre within the World Eaters Legion that served as a dedicated bodyguard unit for their Primarch Angron (whether he needed one is another matter) during the Great Crusade and the Horus Heresy. In battle they fought encased in Terminator Armour and carried the most savage weapons the XII Legion possessed. This warrior band had only twelve members, and access to its ranks was only attained by defeating a Devourer in single combat to the death or, should one of its number fall in battle against an enemy, a successor was selected by a contest open to all Astartes in the Legion, only one of which would survive.

History
When the War Hounds were reunited with their Primarch, the XII Legion were soon influenced by Angron's cultural beliefs and blood rites that would become an important part of the World Eaters' core beliefs as the culture within the XII Legion shifted to ever more violent and bloodthirsty mores and values. These became quickly echoed in the shifting skein of the Legion's own rites and ceremonies, which soon disappeared altogether and were replaced by Angron's own red code of butchery and savage competition. Trial by combat quickly became the Legion's preferred route of settling disagreements within its ranks, and bloodletting by warriors in open discord was an honourable thing both in Angron's eyes and that of his Legion. Here also could one of higher rank be challenged for the right to command, although such rare contest were always to the death. The most revered measure of this latter practice was membership of the Devourers.

In the wake of the sweeping changes instituted by Angron upon the XII Legion the elite unit known as the Devourers were formed in honour of their lord. This cadre consisted of a dozen Legionaries. Access to its vaunted ranks was achieved through single-combat to the death within the World Eaters' fighting pits. If a Devourer was slain in battle against a foe, a contest open to all Legionaries within the World Eaters was held to determine who would be a worthy successor to fulfill the former Devourer's position. Once considered a great honour, over time a position within this cadre was barely acknowledged by the Primarch, as his neural implants known as the Butcher's Nails slowly ravaged Angron's mind, eroded his mental stability and slowly damaged his capacity to reason.

Over a century later, by the time of the Horus Heresy, the Devourers would constantly lurked behind their lord, their Primarch hardly sparing them a glance. To be one of Angron’s bodyguards was no longer considered an honour, despite how fiercely the World Eaters’ champions had fought for it in the first, optimistic years. Angron ignored them no matter where they went, never once fighting alongside them in battle. In their Terminator plate, they’d never managed to keep up with their liege lord, and they were as prone to losing control to the Nails as any other World Eater, meaning any hope of them fighting as an organised pack was a forlorn one at best. These warriors who'd spent a century learning to swallow their pride, pretended that they weren’t ignored by their Primarch.

Angron's so-called "bodyguards" annoyed him to no end, as if he needed them. Even their name annoyed him -- "Devourers," as if he had named them himself, as if they were the Legion's finest. Their intentions were pure, for they sought to honour their gene-father. It wasn't their fault that they were left behind in every battle. Ironically, the Devourers weren't even the Legion’s fiercest fighters, any more. Many of the World Eaters' finest warriors refused to challenge for a place in their ranks. When asked about joining the Devourers, Angron's Equerry Khârn merely laughed at the sheer absurdity and the Legion Apothecary Kargos "Bloodspitter" had beat one of their number in the fighting pits, and carved his name into the poor bastard’s armour with a combat knife out of spite.

Following the end of the Horus Heresy, the World Eaters Legion consumed itself in a bitter internecine conflict that saw it fractured into countless smaller warbands during the Battle of Skalathrax, instigated by Khârn, the former Equerry of Angron and a Khornate Berserker, who earned the enmity of his Legion for his infamous actions upon the Daemon World, earning the epithet "Betrayer." The remaining Devourers founded their own Khornate warbands as Chaos Lord or joined other warbands as Chaos Champions of Khorne.