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The Legio Mordaxis ("Deathdealers") is a Traitor Titan Legion of the Dark Mechanicum. Throughout the Great Crusade the Deathdealers were closely associated with the Word Bearers Legion, a partnership that ultimately led to their corruption by Chaos.

In the year preceding the start of the Horus Heresy, the Dark Apostles of the Word Bearers infested the god-engines of the Deathdealers with a deadly techno-toxin which made their very presence corrupting and decaying to all those around them.

Legion History[]

Legio Mordaxis Warlord-Class Titan

Legio Mordaxis colour scheme as displayed by the Warlord-class Titan Sin-Eater.

The Legio Mordaxis was once a Loyalist Titan Legion of the Adeptus Titanicus, created some time before the tumultuous Age of Strife. Hailing from a highly toxic world, during this troubled era the Legio weathered the constant Warp Storms and ravages of the deadly environment of their homeworld beneath the protective barriers of environmentally sealed manufactoria.

They only emerged to eradicate those who would dare encroach upon their homeworld, wiping out any threat that dared assail it.

Once they were rediscovered by the Imperial expeditionary fleets of the Great Crusade and brought into the Imperial fold, the Legio Mordaxis deployed alongside several Legions of the Legiones Astartes, most notably the Word Bearers, at the forward edge of the Great Crusade.

The Legio Mordaxis had once been pure and loyal soldiers in the Emperor's armies during the Great Crusade. On the eve of the Horus Heresy, they were brought low by a malevolent machine plague devised by the Dark Mechanicum and unleashed by the Dark Apostles of the Word Bearers.

This techno-virus infected the Legion's princeps, stripping them of their will and individuality until they remained little more than puppets slaved to the will of their Titans' corrupted Machine Spirits (artificial intelligences).

Horgoth Nyr, the princeps maximus of the Legio Infernus ("Fire Masters") callously exploited the weaknesses of his allies, and manipulated the Legio Mordaxis and others into sending a measure of their strength to aid the Traitor primarchs, so that he might engage in the true business of bringing the Five Hundred Worlds of Ultramar to their knees in the course of the Heresy.

Accurate records of the actions of Legio Mordaxis Titans following their declaration for the cause of the Warmaster Horus remain elusive, for their very presence corrupted any machines they came into contact with.

Testimonies extracted from Solar Auxilia detachments after the Siege of Castra Tanagra speak of a Deathdealers Titan bearing the weathered colours of the Legio Mordaxis, one of which matched the description of the Reaver-class Titan Irkalla.

Once honoured for its past deeds during the assault upon the Fortress of the Illucidian Barons, the god-engine that walked upon Talassar was profoundly different, each step ponderous and heavy, as if weighed down by the corruption that had taken root within it.

Notable Campaigns[]

  • Shadow Crusade (007-008.M31) - In the wake of the disastrous Battle of Calth, the Word Bearers and the World Eaters Legions, along with the Legio Mordaxis, Legio Infernus (Fire Masters) and Legio Audax (Ember Wolves), launched the Shadow Crusade against the Realm of Ultramar, bringing ruin and despair to the Five Hundred Worlds. Loyalist forces fought back fiercely, but were often outnumbered or outgunned, and often taken by surprise by those they once counted as allies.
  • Crusade of Iron (ca. 008-010.M31) - In response to the Traitor Legions' assault across the Five Hundred Worlds of Ultramar during the Battle of Calth and the Shadow Crusade, the Loyalists within the region declared the Crusade of Iron. Spearheaded by the Titans of the Legio Praesagius, they led their allies from the Legio Oberon, Legio Lysanda and dozens of Imperial Knight households to isolate the Traitor forces and slaughter them piecemeal. The Legio Mordaxis would take part in a number of notable campaigns against the Loyalists during this particular crusade.
    • Defence of Tyros (ca. 008.M31) - During the Defence of Tyros, a new and terrible ally of the Legio Praesagius entered the fray. Unheralded, black armoured Psi-Titans of the Ordo Sinister appeared on the battlefield. Like a giant apparition of death, the Warlord-Sinsiter Titan Occedentalis-Eurytus spread dismay and ruin among the Titans of the Legio Mordaxis and the Knights of House Ærthegn. Supported by only a handful of Loyalist Knights and Titans, the Warlord-Sinister infected Knight Nobles and Titan princeps with visions of despair and defeat. Their vox-net crippled, and their commanders imprisoned by their own doubts, the Traitor forces became easy prey for the Loyalists, who drove them from the cities of Tyros and hunted them across the world's vast Alkaline Badlands.
    • Purging of Haverlund (ca. 008.M31) - During the Purging of Haverlund, the Sons of Konor made their re-appearance during the ongoing conflict. This was an alliance of Blackshield Knight houses comprised of minor Knight households from the Eastern Marches that had been turned away by lords who pledged their strength to neither Emperor nor Warmaster. Some did not even give reason for their disobedience, or observe even the smallest measure of respect for the Forge World of Gantz, the homeworld of the Legio Praesagius, when summoned. Fighting under the command of the Blackshield Knight known as the Crownless King, these Knights sought independence from both Horus and the Imperium. After Haverlund's fall into rebellion, the Crownless King and his households began a long campaign to free it from its traitorous masters. This culminated in the Battle for Victory Plaza, which saw scores of Knights fight to bring down the Legio Mordaxis Warlord Titan Noctis Sanguinia and its Axiom maniple.
    • Dark Waters (ca. 009.M31) - Despite their defeat on Espandor, the Loyalist Titan Legions eroded the strength of their enemies across the Five Hundred Worlds. The Legio Mordaxis, the Traitor Titan Legion that had been transformed by the machinations of the Word Bearers Legion, were charged by their Legio Infernus allies to hunt down and destroy Mechanicum forces across the western regions of the Realm of Ultramar. Here, their spies came to the fore and, following reports from Traitors among the Loyalist ranks, the Legio Mordaxis fleet sailed for the remote water world of Zarathusa Secundus. The people of this isolated world existed on floating cities, whose ancient technologies farmed the planet's geothermal wealth. The Loyalists had recently pacified an uprising sparked by Dark Mechanicum cells on the planet, and the aftermath of that war was still evident throughout its shallow seas. The Traitors commenced their attack as the Loyalist forces, commanded by Princeps Tesarius Solomere Krane of the Legio Lysanda, aboard his Reaver-class Titan, Purantum Bellos, awaited extraction upon the principal landmass of Zarathusa, known as the Aquila Atoll. The Traitors seized control of both the planet's orbit and the Loyalist vox-net, masquerading as loyal servants of the Imperium until the trap was sprung. As landers approached the surface of Zarathusa, they revealed themselves not as the intended extraction ships but rather transports carrying the Titans of the Legio Mordaxis. Desperate to deny the atoll to the invaders, the Legio Lysanda and the Imperial Knights of House Vornherr scrambled to form an effective defence, aware that retreat was not an option without abandoning those ground forces unable to wade through the seas of Zarathusa; seas that turned black as the battle raged and toxins that had ravaged the Legio Mordaxis polluted the ground they walked upon. Despite their valiant efforts, the Loyalist forces were led into a cunningly laid trap by the Dark Mechanium allies of the Legio Mordaxis. Much later, the Loyalists would learn the fate of Zarathusa Secundus and its defenders, though not before the corrupted remains of the Purantum Bellos was encountered on Drooth II, along with the blackened Knight armours of dozens of House Vornherr scions, now enslaved to the Legio Mordaxis machine curse. As the war raged on, the devastation it left in its wake increased the intensity of the storms and the frequency of the tidal waves that tore across the land, even as techno-toxins flowing from wounded Legio Mordaxis Titans left a permanent stain upon the world's ecosystem.
    • Battle of Drooth II (009.M31) - Known for its burning sand-like mineral deserts, Drooth II was originally populated solely by a research station and listening outpost, placed there by the Ultramarines Legion to watch over the eastern edge of Ultramar. This outpost was quickly overrun by the Dark Mechanicum as war engulfed Ultramar and turned into a profane manufactorum capable of churning out debased weapons infused with powers pulled from the Warp. It was here that the Traitors commanded by Horgoth Nyr chose to make their stand against the Loyalist forces, aware that the veil lay thin and the entities within the Warp were easily called upon should the Traitors lose the advantage. In preparation for the Loyalists' arrival, the defences of the outpost were strengthened, denying approach from orbit and forcing any invader to land far from the Traitors. With both sides drawn to the world, the stage was set for a battle of cataclysmic proportions. Gathering what remained of those forces committed to the Crusade of Iron, the Loyalists set sail for Drooth II and the battle that awaited. Titans of Legio Mordaxis, Legio Infernus and Legio Audax assailed the Loyalist Titans of Legio Praesagius, Legio Lysanda, Legio Oberon and Psi-Titans of the Chamber Occedentalis, as they advanced upon the Dark Mechanicum's factorums and reactors. On all sides of the outpost, dozens of Titans fully engaged in brutal exchanges of fire. From amongst the ranks of the Loyalist Titan Legions the Psi-Titans let their might be felt. The darkly majestic Warlords of the Ordo Sinister unleashed torrents of psychic energy into the Traitor forces rising against them, invisible beams and blades of power carving through plasteel and ceramite plating as if they weren't there. As the battle continued to rage, a Psi-Titan was pulled down by a pair of Traitor Titans that ripped its reactor open. Crashing down to the planet's surface, the rift between realspace and the Immaterium tore wide once more, and hell came with it. Finally Princeps Ultima Dae Vergos of the Legio Praesagius confronted her hated rival Horgoth Nyr from the Legio Infernus within the heart of the Dark Mechanicum outpost. The two sworn enemies tore into one another with all the malice and spite they could muster. Despite landing a significant blow which felled the enemy Warlord Titan, it rose once again like a revenant from the dead. Instead of turning on the revenant Titan that marched towards her position, the princeps ultima turned her Titan's weapons upon the forge-fane, and with a mighty barrage of cannon fire, obliterated the base's magnetic locks holding the gravity elevator that extended into orbit. The resulting destruction caused secondary explosions to erupt across the outpost. From orbit, the Loyalist fleet witnessed the destruction of Drooth II, the space elevator collapsing in on itself like a headless serpent, its coils crashing down to envelop huge swathes of the planet below -- and the Titans still fighting there. Though the Horus Heresy would drag on for years yet to come, the Crusade of Iron ended that day on Drooth II.

Legion Combat Doctrine[]

The corrupted princeps of the Legio Mordaxis exist in a world of constant torment, linked as they are to a god-engine ravaged by disease, forging them into lumbering behemoths nigh-immune to pain.

Many of these princeps have welcomed the changes wrought upon them, accepting every "blessing" offered by the Dark Gods. Though they have broken many oaths, the princeps still believe in the strength of brotherhood.

Legion Specific Wargear[]

  • Toxin Nodes - The Dark Mechanicum engineered methods for exploiting the internal corruption of the Deathdealers' Titans into their weapons, enabling them to spit forth disease.

Notable Titans[]

  • Mark of Ruin (Warlord-class Titan) - The Mark of Ruin was a Warlord Titan command by Princeps Senoris Hakoth Rul, who led the Legio Mordaxis during the Battle of Zarathusa Secundus.
  • Noctis Sanguinia (Warlord-class Titan) - The Noctis Sanguinia was a Warlord Titan that led an Axiom maniple of various Titans of the Legio Mordaxis during the early campaigns of the Horus Heresy. Unfortunately, it would meet its end at the hands of the Sons of Konor, a force comprised of Blackshield Knights, upon the world of Haverlund during the Battle for Victory Plaza. With scores of Knights, the Sons of Konor brought down the mighty Legio Mordaxis Warlord Titan and its fellow Traitor Titans.
  • Sin-eater (Warlord-class Titan) - Sin-eater was a notable Warlord Titan of the Deathdealers that had last been seen during the conquest of Hnudiax in the year 999.M30, and would not be seen again until the invasion of Zarathusa Secundus in 009.M31. The changes wrought upon the Legio Mordaxis were plain to see upon its form, oily fluid seeping from its joints with every step. As Sin-eater strode towards the Aquila Atoll, the water around it blackened, that Chaos taint harboured within the Titan corrupting all around it. More troubling still were the sorrowful cries that echoed from the Titan when attempts were made to hail it, the princeps of Sin-eater consumed by eternal agony, now enslaved by the machine curse unleashed upon the Titan Legion by their Word Bearer allies.
  • Irkalla (Reaver-class Titan) - Irkalla was a formerly Loyalist Reaver Titan that became corrupted by the techno curse enacted by its Legion's allies among the Word Bearers. Once lauded for its honourable service during the Great Crusade, when it was once again encountered during the subsequent campaigns of the Horus Heresy, it had been became a cursed revenant war-engine that corrupted the very ground it trod upon.

Notable Legion Personnel[]

  • Princeps Senioris Hakoth Rul - Rul commanded the Warlord-class Titan Mark of Ruin during the Battle of Zarathusa Secundus. The machine disease that infected him pumped through his MIU into the god-engine. There was little left of the man Rul had once been, the black blood of his cursed Titan having turned him into an extension of its dark Machine Spirit. Rul only desired the destruction of his enemies and to spread the machine curse carried by his Legion. This was why his Titans pushed their reactors even as they were descending on Zarathusa, and vented their corrupted plasma into the seas, the black liquid infecting everything it came into contact with. The Traitor Titans of the Deathdealers spread the poison of their machine curse, its black plasma residue becoming huge oil slicks that dominated thousands of square kilometres of ocean. His ultimate fate following the fighting on Zarathusa Secundus is unknown.

Legion Allies[]

Knight Houses[]

Space Marines[]

Legion Appearance[]

Legion Colours[]

The colours of the Legio Mordaxis are purple and black with gold trim.

Legion Badge[]

The Legion badge of the Legio Mordaxis takes the from of a triumvirate of skulls; a single skull facing forward and centred upon a pair of skulls looking off to either side.

This symbol is centred within a pair of white, open-faced circlets; a circle within a circle, on a field of black.

Followers of Nurgle[]

Though the Legio Mordaxis has a very similar three-headed symbol of stacked skulls, reminiscent of that used by the Death Guard Traitor Legion, utilises toxic weaponry and destroys the environment through the corruptive power of Chaos wherever their god-engines walk, they are not explicitly stated to be followers of the Chaos God Nurgle.

However, given their history, tactics, weaponry and heraldry, they are likely servants of the Plague God.


  • Adeptus Titanicus: The Horus Heresy - Shadow and Iron (Specialty Game), pp. 8-10, 13-14, 34-36, 70-71, 92
  • The Purge (Novella) by Anthony Reynolds, pp. 44-45