Athame

An Athame, was a unique ritualistic knife with unusual abilities, utilised by the Word Bearers Traitor Legion during the Battle of Calth in the opening days of the Horus Heresy in the early 31st Millennium. Several of their human Chaos Cultists soldiers on the surface of Calth also utilised ritualistic weapons known as athames, though these were rather small, mundane versions of the weapon, which was made out of flint or some kind of crude metal. Blessed by the Dark Apostles themselves, these knives were considered a mark of high status within the ranks of both the XVII Legion and the Chaos Cults. These so-called Shards of Erebus were esoteric weapons that possessed special properties that enabled it to rend the skein of reality, allowing the wielder to step through the Immaterium and cross vast distances, and exit out into reality, whether aboard a vessel traveling through the Warp, or onto a completely different world. The whereabouts of these fell weapons following the Battle of Calth are unknown.

History
To further enable his ambitions to help the cause of the Warmaster's rebellion, and achieve his overall goal of overthrowing the false deity known as the Emperor, Erebus had interpreted the will of the Chaos God and devised the means in which to achieve his lofty goals. The Dark Apostle took the Kinebrach Anathame, the blade that had mortally wounded Horus and brought him "illumination" to the Primordial Truth, and prepared to perform an ancient ritual. Within his personal chambers aboard his flagship, the Destiny's Hand, Erebus presented the sword to the statues of the four Ruinous Powers, calling out prayers and incantations, saluting the dread lords of the Warp, each in turn. What he was doing here was to remain secret until the allotted time. He had the doors to this chamber barred and his bodyguards standing watch outside. Cowled artisans stood read at the Dark Apostle's side – Guldire, chief among the Erebus's Warpsmiths, shadowed by his foremost apprentices. Though it seemed a sacrilege to do what he must do, the weapon had already served its purpose – in this form, at least.

Utilising a rune-inscribed hammer from an apprentice Warpsmith, Erebus brought the hammer's head down and began to reforge the baleful weapon into its new forms. With his dolorous hammer blow, the Dark Apostle was able to break off a finger-length sliver of the blade's weird alloys. Though diminished, the anathame was yet whole. Seven more times did Erebus break the dark blade; seven more shards were commended to his Warpsmiths, until finally he was done. The shards had been knapped from the blade by the his own hand, in accordance with the old rituals. Then they were grown in the blood of the Neverborn, and fashioned into fine implements – each alike, but no two exactly the same. The fracturing of the anathame was but the first step down a longer path. The diminished blade would be disposed of as the Dark Apostle had originally been instructed.

Six daggers were forged for those Word Bearers who would lead the assault against the Ultramarines Legion on Calth; Dark Cardinal Kor Phaeron, Chief Librarian-sorcerer Quor Vondar, Phael Rabor, Morpal Cxir, Foedral Fell, Holl Beloth. The seventh was to be carried by Sergeant Kolos Undil, leader of Erebus's cadre of bodyguards. The eighth and final dagger was forged for himself. Each of these servants of the Dark Gods could feel the untapped power that emanated from the dark blades. These were no mere ritual athames, but true tools of the Gods. Although all the blades were similar – hilts bound in black leather or wire, marked with golden runes and ties with devotional ribbon – the blades were all markedly different. Crooked, or straighter, one forked, another with waved edges. All were, however, of the same flinty black metal that pained the eyes. Though initially insulted that the bearer of one of these daggers was a mere sergeant, Erebus assured his fellow Word Bearers that Undil possessing one, would not diminish the potency of the rest, nor the honour in carrying one. Undil was a renowned warrior within the XVII Legion, as devout as his master and almost as devious.

Erebus informed the bearers of the athames that the blades were gifts of the gods. They possessed the power to shield the wielder from harm, or to aid him in the working of great sorceries. However, these esoteric weapons were dependent on the ability of he who carried them. These athames were not merely ritual tokens, but tools of enlightenment. A wound from them could turn the mightiest here to the Traitors' cause, opening their eyes to the majesty of Chaos, and the perfidy of the Emperor. The shards would be present as he needed them to be, and the blood they would shed could only hasten the future he had foreseen, even if nothing else. If the Word Bearers Primarch Lorgar intended to rid himself of Erebus, then he would be disappointed. That the eight Shards of Erebus now also offered his fellow commanders the opportunity of escape from Calth was unimportant to him. Whether or not they would learn how to effect flight through the Immaterium should they need it, that was something he would leave to the will of the gods.

During the Battle of Calth, the Ultramarines 4th Company, under the command of Captain Remus Ventanus, converged on the fortress of Leptius Numinus. The loyalists were able to power up the palace's data-engine and Vox assembly in order to contact other possible surviving Ultramarines, Imperial Army or Loyalist Mechanicus forces. Ventanus eventually established short-range communications with other besieged Ultramarines units. His situation was not unique. All of the Ultramarines on Calth's surface found themselves mired in the same predicament. Soon a large horde of Traitor forces commanded by the XVII Legion's Commander Morpal Cxir had already encircled the palace and launched an attack against its small group of valiant defenders. Terrible carnage was inflicted upon the Loyalist defenders by packs of horrific daemons summoned from the Empyrean as they punched through any breaks within the defensive line. During the ensuing battle, Captain Ventanus was unintentionally utilised the athame taken from Morpal Cxir in an earlier skirmish, and defeat the daemon Samus with it. At the time he had no other weapon at hand, and was amazed by the blades lethal potency. When his sergeant, Kiuz Selaton suggested gathering other such similar blades from the fallen Word Bearers and their human servants to utilise against the hordes of daemons that now ravaged Calth's surface, Ventanus wisely refused. But he did keep the athame he had used and placed it safely in in his belt.

At the climax of the battle Primarch Roboute Guilliman personally led his elite guard and whatever supporting Ultramarines forces he could muster, to assault on orbital platform controlled by Kor Phaeron and his elite guard. The Dark Cardinal and his warriors each carried an athame dagger. When confronted by the Primarch in personal battle, the Dark Cardinal was able to stun the Primarch utilising his fell powers granted to him by the Chaos Gods. Rendered temporarily helpless, instead of killing the Primarch, Kor Phaeron toyed with the idea of using his blade's innate abilities in an attempt to turn Guilliman to their cause, as Erebus had already done with Horus. Though he held the blade to the Primarch's throat, piercing his flesh, he was unable to strike a fatal blow. Guilliman was able to resist the dark influence of the malefic blade and launched a lethal counter-attack of his own, impaling Kor Phaeron through his chest with his inert Lightning Claws. These mortal blow forced the Dark Cardinal and the Word Bearers to retreat.