Warhammer 40k Wiki
Warhammer 40k Wiki

"If the hallowed Legio made us into giants, then it was the will of the Warmaster that made us gods."

— Princeps Seniores Aedurn Kaum, Legio Interfector

The Legio Interfector ("Murder Lords") is a Traitor Titan Legion of the Dark Mechanicum in the service of Chaos. Formerly known by the cognomen "Lords of Valour," the Legio Interfector was a young Titan Legion, raised from the Forge World of Valeous II during the first years of the Great Crusade.

During that most august undertaking, the Lords of Valour acquitted themselves with honour and bravery, adding numerous campaign triumphs to their war banners.

All that changed on Isstvan III, when they were subverted to the will of the Warmaster Horus. After that dark day, the Legio Interfector were known by a new name: the Murder Lords.

Madness has now taken root within the ranks of the Legio Interfector, whose princeps turn for guidance to the voices of the Ruinous Powers which now whisper constantly in the quiet of their minds.

Legion History[]

Murder Lords Warlord Titan

Legio Interfector Pre-Heresy colour scheme as displayed by the Warlord-class Titan Abhorrent.


The Legio Interfector has borne two common appellations since its creation, both reflections of the overriding demeanour of the princeps who served beneath its banner. The first was acquired during the Great Crusade, the cognomen of "Lords of Valour" bestowed upon the Titan Legion in honour of the courage and steadfastness of princeps who stood as exemplars for the ideals of the Great Crusade.

Yet the machinations of powers far beyond the ken of most plunged the Titan Legion into madness and treachery. By the end of the Horus Heresy, the virtue of the Legio Interfector had long been eroded, replaced by a canker that had taken root within its ranks, stripping away sanity and independence from its princeps until nought but subservient fiends remained.

The opening years of the Great Crusade saw rapid growth for the Imperium, with many worlds eager to join the Emperor's newfound empire. However, as Humanity pushed outwards it encountered firmer resistance, both from the varied xenos species that sought Mankind's destruction and resistant strands of Humanity that opposed subservience to the Emperor. This abundance of foes heaped great pressure on the military arm of the Imperium, motivating the Terran War Council to search for new forces to aid expansion. As part of this initiative, the Forge World of Valeous II, newly inducted into the Imperium and eager to benefit from the knowledge of Mars, was chosen as the founding world of a new Titan Legion.

Named the Legio Interfector, the foundation of this nascent Titan Legion was built from shipments of unconsecrated god-engines dispatched from Lucius and Graia, while Martian delegations toiled to revitalise the decaying industry of the planet and sanctify its forge-fanes in preparation for a new generation of Titans. In short order, Valeous II was transformed and deemed fit to house a Titan Legion in its own right. The final order was to christen the Legio Interfector in battle and the Forge World's first demi-legio, consisting of three-quarters of the Titan Legion's strength, departed for distant stars.

Murder Lords Warhound Titan

Legio Interfector Warhound-class Titan Fire of Betrayal

The tragedy that was to befall the Legio Interfector was not one of its own making but sparked by a simple twist of fate. The first detachment of Legio Interfector Titans dispatched from Valeous II were intended as support for elements of the Ultramarines Space Marine Legion fighting in the Ultima Segmentum but was instead cast adrift by unpredicted Warp currents. This abrupt change of course saw the Titan Legion cast into a war zone commanded by Horus Lupercal, his Luna Wolves engaged in a deadly conflict with the xenos-forged Abominable Intelligence known as the Chroxius Myriad.

The arrival of the Legio Interfector quickly reversed the course of the war, its tireless guns throwing back the mechanical horde and laying waste to their nexuses. After a further seven solar months of conflict, the xenos were defeated, a conclusion Horus attributed to the skill and valour of the newly-forged Titan Legion. In recognition of its service, the primarch authorised the reassignment of the Legio Interfector to his own forces and bestowed upon it the cognomen of "Lords of Valour" so all would know the honours it had earnt.

For the remainder of the Great Crusade, the Lords of Valour lent its guns to Horus and his Legionaries, with freshly-raised demi-legios dispatched to expeditionary fleets manned by the Luna Wolves. To the Titan Legion, the primarch became an idol, its princeps frequently proclaiming him to be a model by which all servants of the Imperium should compare themselves. In an effort to be exemplars of Imperial values, the Legio Interfector threw itself into the most deadly of conflicts and, with each new victory, proved that the name given to them by Horus was well-earned.

Yet the devotion the Legio Interfector held for Horus Lupercal was to be repaid only with treachery.

Horus Heresy[]

Murder Lords Warmaster Iconoclast Titan

Legio Interfector Warmaster Iconoclast Titan Hand of Sin

When the primarch was appointed Warmaster of the Imperium, the Titan Legion rejoiced, its princeps clamouring to serve alongside him. The tides of war were to prevent the Lords of Valour from walking the same battlefield as the Warmaster until a muster was called to suppress rebellion stirring in the Isstvan System. Missives were dispatched and threescore god-engines of the Legio Interfector were sent, called to battle by the personal request of the Warmaster himself.

The means through which madness took root within the Titan Legion is unknown, for none privy to such details remains loyal to the Emperor or lucid enough to give testimony. Fleet logs suggest the Legio Interfector joined the Warmaster's order of battle for three solar days and then departed once more, its numbers scattering across the galaxy. In such a short time, the personalities of its princeps were twisted and subverted, minds given over solely to the worship of the Warmaster. Were such a malady contained solely to those of the Legio Interfector that were present at Isstvan III then perhaps the legacy of the Titan Legion may have survived the turmoil of the Horus Heresy, yet the machinations of the Traitors left no room for half measures.

As the Warmaster moved to eradicate the Loyalist Astartes survivors on Isstvan III, the Traitorous elements of the Legio Interfector were tasked with reuniting the Titan Legion upon Valeous II. Akin to a virulent plague, the madness inflicting the princeps who had been twisted at Isstvan III spread amongst those born of the Forge World, until both the Titan Legion and the Tech-priests of Valeous II held no passion in their hearts save a desire to bring ruin in the Warmaster's name.

Madness quickly took root within the ranks of the Legio Interfector, whose princeps now heard the call of a higher power. The Dark Gods' constant sibilant whispers of glory and power infected the members of the Legio with an all-consuming lust for slaughter and bloodshed. From that day, the Lords of Valour were no more, the psyche of the Titan Legion hollowed out and replaced with insanity. When next the Legio Interfector walked the galaxy it did so at the behest of the Traitors, obliterating worlds who refused to accede to demands for subservience.

War sirens perched atop the carapace of the Titan Legion's god-engines broadcasted the gibbering prayers of its crews, interspersed with pleas for blood and whispers in unknown tongues that unleashed waves of nausea on any who heard them. Gone were the precise tactical manoeuvres that were once characteristic of the Legio Interfector, replaced instead by erratic behaviour fuelled by the madness that dwelled within the heart of each Titan. From the dark day when the Legio Interfector was undone by the schemes of one they held in highest regard, a new title was worn by the Titan Legion -- the "Murder Lords."

41st Millennium[]

Eydolim System

Departmento Cartographicae map of the Eydolim System

The Legio Interfector is known to have supported an effort made by the Word Bearers splinter warband, the Foresworn, led by the Daemon Prince Kor Megron, to topple the Shrine World of Eydolim in 946.M41.

During the days of the Great Crusade, a company of the Word Bearers Legion under the command of Kor Megron was stationed on Eydolim to assist Human colonists in settling the planet. As was customary for them, the Word Bearers spread amongst the populace the belief that the Emperor of Mankind was a god incarnate -- a creed directly conflicting with the atheistic Imperial Truth, which was the official doctrine of the Imperium in that era.

When the company turned to the worship of Chaos alongside the rest of its Legion following the Pilgrimage of Lorgar, Kor Megron and his followers swore that their great work would not be complete until every last icon of the False Emperor was cast down and the Imperium itself no more than a distant memory. Each sealed this pact with blood and they anointed themselves as "the Foresworn."

They continued on this quest throughout the millennia after the end of the Horus Heresy, though their greatest goal had always eluded them -- the undoing of the magnificent works they had done on Eydolim in their former veneration of the Emperor.

To this end, in 946.M41 the Foresworn assembled a force of several Chaos Space Marine warbands -- the Red Corsairs, splinter warbands from the Black Legion, the Iron Warriors, the Night Lords and the World Eaters Legions, and secured the support of Dark Mechanicus Traitor Titans.

The Iron Warriors and Red Corsairs forces struck at Lector's Lowell, a Forge World located in the same star system as Eydolim, hoping to plunder the vast resources of the world's weaponariums for which the planet was rightly famed.

The forgemasters of Lector's Lowell were aware of the incoming Chaos assault, and rallied their Skitarii regiments to defend the world.

Soon after the Chaos Space Marines made planetfall, however, it became apparent that the Forge World stood little chance, as the Heretics were supported by the Traitor Titans of the Legio Interfector, a force the Skitarii could not hope to counter. Lector's Lowell was in dire straits.

In response to attacks carried out throughout the system, a sizable portion of Crusade Group Black Gate was diverted from its original assignment to support Imperial efforts in the Damocles Gulf to defend the world of Eydolim.

Units of the contingent, including nine regiments of Cadian Shock Troops as well as smaller dispositions of other Astra Militarum regiments, bolstered the undermanned Planetary Defence Force, and its grateful marshal offered overall command to the far more experienced Cadian commanding officer, who accepted the commission with humility.

Eventually, the Heretic Astartes made planetfall, and steadily pushed Imperial forces back, overcoming all resistance, until they finally reached the capital city of the world. Outmatched at every turn, the defenders looked to the heavens in desperation -- and beheld a miracle. The scions of Ultramar had arrived.

While fighting the aliens of the T'au Empire, the Ultramarines 2nd Company and a force of 1st Company Veterans accompanying them received orders from their Chapter Master, Marneus Calgar, to relocate to Eydolim.

Interfector Titan

A Legio Interfector Reaver-class Titan

Captain Cato Sicarius, with barely disguised enthusiasm, hastily diverted his force. Aboard the Strike Cruiser Valin's Revenge, the Ultramarines prepared to face their Traitor brethren. As the Heretics swarmed towards Eydol City, the Space Marines deployed their entire strength to support the Astra Militarum.

First contact between the Ultramarines forces and the Traitors took place in the munitorum district outside Eydol City. A small task force led by Epistolary Casmus daringly assaulted the Chaos Titans of the Legio Interfector which brazenly strode into the urbanised area, and succeeded in destroying one of those towering machines, in addition to damaging several others. This Imperial task force retreated only when a unit of the Red Corsairs moved to clear them out.

The two forces proceeded to clash in the climactic engagement of the campaign, the Battle of Eagle Gate. Eagle Gate was the sentinel of the city of Eydol's east road, the central point of an imposing curtain wall.

Reinforced with plascrete and bristling with automated turrets, it was a redoubt which no attacker had penetrated in the past, and yet during the Battle of Eagle Gate it was breached in several places -- long range bombardment tearing holes in its right flank, Titans of the Legio Interfector blasting great chunks from the walls on the left flank, and Khornate Space Marines supported by the Foresworn hurling the gates themselves open.

At the end, the wrath of the Foresworn and their allies was halted before the Gate of Martyrs -- the great eastern portal of Eydol City. There, the remnants of the Imperial forces made their last stand as Kor Megron hurled himself at the defenders, eager to slaughter them all.

Cato Sicarius stood defiantly before him as the Daemon Prince brought his weapon down in foul sweeps, battering the Space Marine captain with such ferocity that his knees buckled and his finely crafted Power Sword was notched and chipped.

Kor Megron stomped Sicarius to the ground and raised his weapon triumphantly. The final blow never came, however, as a lone Imperial Guardsman, upon witnessing the dire straits the captain was in, hurled himself at the daemonic monstrosity, careless for his own safety, and pierced the Word Bearer's flesh with his bayonet.

Kor Megron turned his attention to the brave soldier, and burned his body in a burst of Warpflame. This distraction allowed Sicarius to act, and he hastily thrust his sword upwards, piercing the Daemon Prince's breastplate and driving the blade into his corrupted heart. With a deafening scream, Kor Megron was banished to the Warp.

Disoriented by the loss of their leader, and worn to the breaking point by the Imperial defenders, the Chaos forces began to fall back. For the Imperium, a reprieve had been bought at great cost. For the legions of Chaos, there would be another reckoning...

Notable Campaigns[]

  • Isstvan III Atrocity (005-006.M31) - The Warmaster Horus revealed the terrible scale of his treacherous ambition when he engineered the Betrayal at Isstvan III, purging his own and three other Legiones Astartes of those who could not be relied upon to swear to his cause. The slaughter is made all the more terrible by the alliance of Legio Interfector (then known as the "Lords of Valour"), Legion Mortis, Legio Audax and Legio Vulpa, whose god-engines are impervious to the Life-Eater virus unleashed against the betrayed Loyalists, and which stride through the firestorms as towering and vengeful giants of legend. After the events of this atrocity, the Legio Interfector would be known forevermore as the "Murder Lords".

A Warhound-class Titan of the Legio Intefector in combat at the Battle of Molech during the Horus Heresy.

  • Battle of Molech (009.M31) - Molech was a Knight World ruled over by House Devine ever since the Emperor Himself led an expedition to bring it into the fledgling Imperium and left a significant garrison there. The planet thrived under the rule of Devine, the populace of its capital city of Lupercalia never knowing the true reason why the Emperor had taken it upon Himself to lead the force that claimed it. Unfortunately for the citizens of Molech, the traitor Horus knew exactly what lay beneath the city that had been name in his honour -- a Warp Gate which, it was said, had allowed the Emperor to convene with the Ruinous Powers themselves. When Loyalist forces became aware of the Traitor fleet's approach, they mustered at Molech. As well as a trio of Titan Legions -- the Legio Gryphonicus, Legio Crucius, and Legio Fortidus -- there were elements of each of the Imperium's fighting forces, including nearly a dozen Knight Houses which owed fealty to Devine. The Traitor force was equally impressive, featuring no fewer than four Titan Legions: the Legio Vulpa, Legio Interfector, Legio Vulcanum I, and the infamous Legio Mortis. As the Warmaster unleashed a massive coordinated assault, the planet's defenders were thrown into disarray when the Plasma Reactor of an Imperator-class Titan was destroyed. Thousands of Loyalists were immolated in a blinding flash as a miniature sun erupted from the Titan's core to leave a smoking crater half a Terran mile wide. In the wake of the catastrophic blast, the spearhead of Traitor Titans marched through the gap in the Imperial lines. At the height of the battle, House Devine revealed its true allegiance to the Warmaster, its treachery unveiled at a pivotal moment, heralding a slaughter from which only a handful of Loyalists escaped. Caught between the treacherous Knights of House Devine and Horus' rampant forces, the shattered remnants of Molech's defenders were slaughtered without mercy. They were totally defeated, so brutally that only one in a hundred of the troops of the Imperial Army survived the campaign. After his passage through the portal into the Realm of Chaos, Horus won the full blessing of the Ruinous Powers as their champion. His drive on Terra seemed unstoppable.
  • Battle of Beta-Garmon, "The Titandeath" (006-013.M31) - The Legio Interfector took part in the long and savage Beta-Garmon campaign, which included hundreds of war zones across dozens of worlds. During this conflict, the Legio Interfector was supported by the Knights of House Makabius. Even before the greater armies of the Warmaster Horus reached the star cluster, the battle lines had long since been drawn, and fighting had been going on for many Terran years. It was a cauldron of battle that would consume millions of lives before its end and see the demise of entire Titan Legions, earning this campaign the dire moniker of the "Titandeath." The Beta-Garmon Cluster, also known as the gateway to the throneworld of Terra, was the last hurdle that the Warmaster Horus' forces had to overcome before they reached the Imperium's capital world. Heavily fortified by the Loyalists, Beta-Garmon would become one of the greatest and bloodiest battles of the Horus Heresy, as well as one of the longest-lasting.
  • Battle of Eagle Gate (946.M41) - As recounted more fully above, the Legio Interfector supported the Foresworn splinter warband of the Word Bearers Traitor Legion in their quest to raze the Shrine World of Eydolim, which they helped to create millennia ago, in the days of the Great Crusade. The Murder Lords took part in a number of engagements throughout the campaign, including an invasion of the Forge World Lector's Lowell, and the final assault on Eydol City, the capital of Eydolim, where the Chaos forces were ultimately thrown back.

Legion Combat Doctrine[]

When the Legio Interfector sided with the Arch-traitor Horus, they did not fully understand the dark powers behind the Warmaster's rebellion. As the Legio fell under the influence of the Ruinous Powers, madness took root within the ranks of the Legio Interfector.

Those princeps not purged by the Warmaster during the opening years of the Horus Heresy were driven insane by the knowledge of their deeds, turning in desperation to the voices whispering in their mind.

In battle, gibbering prayers of darkness and murder spill forth from the Legio's Titans, their war sirens broadcasting the insanity of the crew within. In battle, Legio Interfector Titans can scream out this stream of corrupting static from their war sirens, overwhelming their enemies with madness.

The roots of Chaos have dug deep into the wreckage of the Legio Interfector's Titans. Daemonic energies coil around the Machine Spirits of their god-engines, driving them to extremes of rage and madness.

Legion Specific Wargear[]

  • Static Rounds - The forges of Valeous II were once known for their extensive use of static technologies, weapons created to disrupt and destroy energy barriers. The Legio can still call upon great stores of these weapons, though their shells are now covered in profane Chaos icons to help guide their flight.

Notable Titans[]

  • Hand of Sin (Warmaster Iconoclast-class Titan) - The Hand of Sins depicted above was one of the rare examples of Warmaster Iconoclast-class Titans within the ranks of the Legio Interfector during the Horus Heresy. It is unlikely that the laborious endeavour that is the creation of an Iconoclast Heavy Battle Titan would have been undertaken during the foundation of a younger Titan Legion such as the Legio Interfector. As such, the inclusion of the Hand of Sin amongst the Legio's ranks is a notable one. Analysis of armour debris shed by the Titan following heavy barrages during the subsequent Siege of Attaru's Run, show hallmarks of techwrights associated with Legio Tempestus, while carbon dating places the god-engine's creation at least as early as M27. Extrapolation of such data suggests that the Iconoclast was originally in service to the Legio Tempestus and later gifted to the Legio Interfector. Given that the Loyalist Legio Tempestus on Mars were annihilated during the earliest days of the Schism of Mars, and the Legio's war vaults plundered, it seems likely that the Iconoclast was given to the Legio Interfector as a reward for the Titan Legion's service to the Warmaster Horus.
  • Abhorrent (Warlord-class Titan) - The Abhorrent was once known as the Exemplar, a name gifted to it after its heroic actions during the Great Crusade. When the Legio Interfector was forced to side with the Warmaster Horus, their centuries of valour were cast aside. This very act drove most of the Legio Interfector's Titans mad, twisting their Machine Spirits until they stood as nothing more than pale mockeries of their former selves. Whether out of acceptance or shame for their new path, the Exemplar took a new name as the Legio fought to tear down everything it had once helped to build.
  • Sin of Commission (Warlord-class Titan) - Sin of Commission was one of the Legion's Titans supporting the Iron Warriors and Red Corsairs warbands in their attack on the Forge World Lector's Lowell, which was a stepping stone to the eventual invasion of the Shrine World of Eydolim in the same star system. The presence of Traitor Titans rendered the forgemasters of the world hopeless, as the Skitarii regiments available to them could not possibly fend off the god machines.
  • Fire of Betrayal (Reaver-class Titan) - The sheer ferocity exhibited by the Legio Interfector during the latter years of the Horus Heresy was in stark contrast to their past record. Warhound Titans of the Legion, such as the Face of Betrayal, became infamous for their cruel tactics. Small groups of Interfector Warhounds armed with Inferno Guns would set entire city blocks ablaze in order to divert their foes' attention away from the front line. Such tactics proved effective against the more honourable Titan Legions, who valued the lives of innocents, a virtue the Legio Interfector once possessed themselves.
  • Pax Ascerbus (Reaver-class Titan) - Pax Ascerbus was a corrupted Reaver-class Titan which called itself Teratus and was destroyed by a Legio Fortidus Titan during the Horus Heresy at the Battle of Molech.
  • Purge Master (Reaver-class Titan) - Purge Master was a corrupted Reaver-class Titan that took part in the Battle of Eagle Gate in the Eydolim System in 946.M41.
  • Silence of Death (Reaver-class Titan) - Silence of Death was a Reaver-class Titan which was destroyed by a Loyalist Imperial Knights during the Horus Heresy at the Battle of Molech.
  • Soulmauler (Reaver-class Titan) - Soulmauler was a Reaver-class Titan which was destroyed in the munitorum district outside of Eydol City, the capital of Eydolim, by Space Marines of the Ultramarines' 2nd Company. Several other Titans, amongst them the Purge Master, had been crippled by similar assaults.
  • Bloodweil (Warhound-class Titan) - Bloodweil was a Warhound-class Titan which fought during the Horus Heresy at the Battle of Molech.
  • Lochon (Warhound-class Titan) - Lochon was a Warhound-class Titan which fought during the Horus Heresy at the Battle of Molech.

Notable Legion Personnel[]

None listed in current Imperial records.

Legion Strength[]

From the moment Valeous II was granted the singular honour of its own Titan Legion, its forge-fanes laboured tirelessly to supplement the numbers of god-engines provided to the Legio Interfector by the Forge Worlds of Lucius and Graia. By the onset of the Horus Heresy, their efforts had proven successful, with the Legio Interfector having an estimated strength of 110-140 god-engines, marking it as a Secundus-grade Legio.

Though the Titan Legion lacked examples of more ancient Titan classes such as the Imperator, it maintained a healthy supply of Warlord, Reaver and Warhound-class Titans, along with several examples of Warbinger Nemesis Titans constructed in the final years of the Great Crusade.

Nearly all of this strength was turned against the Imperium by Horus, with few recorded Legio Interfector princeps escaping the madness that gripped the Titan Legion. Unverified reports speak of a small group of Reaver and Dire Wolf-class Titans self-proclaiming themselves as the Lords of Valour operating within the systems surrounding Valeous II. Whether such tales were a product of misinformation or an example of Loyalist Interfector princeps who evaded the malady that afflicted the remainder of this Titan Legion remains unknown.

Legion Allies[]

Knight Houses[]

Space Marines[]

Legion Appearance[]

Legion Colours[]

The colours of the Legio Interfector were originally black with red trim and white flames, but after its fall to Chaos this changed to dark red with decoration in bronze.

Legion Badge[]

The Legio Interfector's badge is a stylised, blood-spattered circlet with a black and white-bladed Kris knife -- a short-bladed weapon with an undulating blade -- pointed downwards. A small white skull icon is situated on the sword's crossguard, centered within a red circlet.


  • Adeptus Titanicus - The Horus Heresy: Traitor Legios (Specialty Game), pp. 78-83
  • Adeptus Titanicus - The Horus Heresy: Doom of Molech (Specialty Game), pp. 7-11, 16, 26-28, 64-67
  • Adeptus Titanicus - The Horus Heresy: Titandeath (Specialty Game), pg. 95
  • Adeptus Titanicus - The Horus Heresy: Rulebook (Specialty Game), pp. 15, 72-73
  • Warhammer 40,000 Rulebook (6th Edition), pp. 384-393, 399
  • Vengeful Spirit (Novel) by Graham McNeill, Chs. 14, 20
  • Warhammer Community - Doom of Molech: What's In The Book (16 Apr 2019)
  • Warhammer Community - What is the Battle of Molech?