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The traitorous fabricator-general of Mars, Kelbor-Hal, after his fall to Chaos.

Kelbor-Hal was the fabricator-general of Mars, the political and spiritual leader of the ancient Mechanicum and the magi of the Cult Mechanicus, during the latter days of the Great Crusade and the Horus Heresy in the early 31st Millennium.

When the Heresy began he and his like-minded magi swore allegiance to the service of the Warmaster Horus and the forces of Chaos in return for the lifting of the Emperor's restrictions on the research and development of heretical technologies, becoming the first leader of what was later termed the "Dark Mechanicum."

In the name of his new allegiance, Kelbor-Hal would unleash the terrible civil war known as the Schism of Mars upon the Red Planet, the sacred heart of the faith of the Machine God.



Kelbor-Hal Fabricator General

Kelbor-Hal, before being corrupted by Chaos.

Kelbor-Hal was once a brilliant magos of the ancient Mechanicum and a deep believer in the doctrines of the Omnissiah. The fact that such an ambitious and duplicitous individual ever rose to prominence and the eventual leadership of the Mechanicum is one of the great tragedies of Imperial history.

It is remarkable to Imperial scholars of today that an individual as extraordinarily gifted as Kelbor-Hal could be so wrong-headed as to bring so mighty and august a body as the Mechanicum over to the service of heresy and rebellion.

When the Age of Strife came to an end, the Emperor of Mankind was determined to bring to fruition His future plans for human unity in a very hostile galaxy. He knew the time had come after the birth of Slaanesh in the 30th Millennium reopened the galaxy to Warp travel and communication to unite all of humanity under one banner, and end inter-human conflict.

With the use of genetically-modified warriors who presaged the development of the first Astartes, He quickly rose to dominance on Old Earth, uniting the once-divided nations of Mankind's birthplace during the Unification Wars. He then set his sights on the wider galaxy, and with His Legions of newly-created Space Marines at the forefront of His mighty expeditionary fleets, the Emperor launched His Great Crusade out into the void.

When the Emperor had first come to Mars after the Unification Wars seeking an alliance between His regime and the powerful Cult Mechanicus, the tech-priests had recognised a kindred spirit; a man of science who valued the power of machines and technological advancement.

As word of the "technological divinity" of this strange golden warrior reached the wider populace of Mars, some tech-priests even began to equate the Emperor with the physical embodiment within the universe of their own Machine God -- the Omnissiah. The Emperor forged an alliance with the Mechanicum through the Treaty of Mars -- an alliance of two empires that marked the true foundation of the Imperium of Man.

In return for supplying the needed materiel for His armies and building a mighty warfleet in the orbital shipyards of Mars' Ring of Iron for His crusade to reunite the stars, the Emperor promised to protect the tech-priests and respect the autonomy of their Forge Worlds and their freedom to continue to practice their faith, despite the official atheism of the Imperial Truth that the Emperor intended to promulgate across all the other worlds of the newborn Imperium.

Kelbor-Hal, then still a magos, had been present when the Master of Mankind had first arrived at Mars on Olympus Mons, but unlike so many of his peers, he had never trusted the Terran interloper.

For the masses of Mars, the Omnissiah was now a tangible being, a golden figure that trod the red surface of Mars, but to Kelbor-Hal and those of his ilk, they believed the Emperor to be a False God who had enslaved the Martian Priesthood to His will with lies.

This bitter resentment, harboured over the next two Terran centuries, would fester below the surface, until such time when this rancorous hatred would boil over into a terrible rebellion against the authority of this False God.

Kelbor-Hal believed the Emperor purposely came to Mars in the guise of the Omnissiah, albeit an incarnate god who came at the head of an army of conquest. The peace that the Emperor had offered the Mechanicum was illusory, a conceit designed to conceal a darker truth.

Kelbor-Hal believed that the Emperor offered peace with one hand whilst keeping a dagger behind his back with the other. In reality, the Emperor's offer was an ultimatum, "Join with me or I will simply take what I need from you."

Faced with a choice that was no choice at all, Kelbor-Hal had been forced to bargain away the autonomy of Mars and see the sacred Red Planet become little better than a vassal world of Terra, Mars ancient rival for leadership among Mankind.

Imminent Civil War[]

Two Terran centuries passed after the signing of the Treaty of Mars, and Kelbor-Hal rose to a position of much prominence within the Mechanicum. He became the fabricator-general of Mars, the master of the Red Planet's mightiest forge city, Olympus Mons.

Kelbor-Hal gathered around him a circle of like-minded magi including Urtzi Malevolus, Lukas Chrom the master of the Mondus Gamma forge, and his trusted personal emissary and confidante Melgator.

The fabricator-general knew he should be proud of his accomplishments, for he had uncovered more of the secrets of technology than any before him and had overseen the longest reign of increasing production quotas in the Mechanicum's history. But pride, like many other emotional responses, had all but vanished as the organic cogitator once housed in his skull had been gradually replaced with synthetic synapses and efficient conduits for logical thought. The fabricator-general was over 80% augmetic by the final days of the Great Crusade, and barely anything that could be called human remained of his birth-flesh, a fact of which he was supremely proud.

The climate on Mars was full of discontent during this tumultuous time in the days just before Horus openly declared his rebellion against the Emperor. There were tense relations between the various Mechanicum magi who governed Mars with sporadic outbreaks of espionage and violence being committed against the various forges that represented the primary sociopolitical units of Mars.

There were even unconfirmed suspicions that the various Titan Legions of the Collegia Titanica, the most potent military forces available to the Mechanicum, had already secretly chosen sides in case of a potential conflict.

Rise of the Dark Mechanicum[]

At the outset of the Horus Heresy, the Warmaster Horus sent Regulus, a Mechanicum representative who had already thrown in his lot with the Warmaster, to Mars to secure the tentative support of the fabricator-general of the Mechanicum for his dreams of rebellion.

Kelbor-Hal was skeptical at first, for the Emperor had been brought to his forge over two centuries earlier, and Kelbor-Hal had been forced to bend the knee to him.

The ruler of the lowly Terran tribes had made empty promises of an equal role in his grand crusade of conquest, but that vaunted equality had never materialised in the fabricator-general's view. The Mechanicum continued to toil in its myriad manufactorums and orbital shipyards across the galaxy's Forge Worlds to provide the Emperor's armies with the needed weapons of war, but received nothing for their efforts but platitudes.

Kelbor-Hal knew Horus Lupercal was a warrior of vision, but Kelbor-Hal wanted to know what he could offer in addition to platitudes.

Regulus explained to the fabricator-general that much had happened since the Emperor took His leave of the expeditionary forces after the success of the Ullanor Crusade and the installation of His favorite son Horus, as the Warmaster and his proxy in command of the Great Crusade.

He assured Kelbor-Hal that alignments had shifted and that new powers emerged from the shadows, offering their aid to those with the strength of vision to heed them. Horus Lupercal was one such individual, and he was now assuredly a friend of the Mechanicum.

When it came time to strike at the Emperor and His Imperium, Horus guaranteed to be a friend to Mars as long as the fabricator-general gave his loyalty -- and his manufacturing capabilities -- over to the cause of the Traitors. Horus also required the fabricator-general to quash any dissent amongst his own tech-priests so that the forces of the Warmaster would be able to launch their bid for supremacy within the Sol System without fear of counterattack.

Any factions loyal to Terra must be brought to heel or destroyed before the Warmaster’s forces reached the Sol System. The fabricator-general informed Regulus that the Warmaster had asked much of him and the Mechanicum already.

The Mechanicum had already delivered, for they had ensured that materiel and weapons were priority-tasked to those expeditionary fleets of the Great Crusade that the Warmaster favoured and had delayed shipments to those not aligned with him. But the Mechanicum had no desire to trade one autocrat for another.

Regulus assured Kelbor-Hal that the Warmaster pledged to return the Martian empire to its former glory, and furthermore, he swore to withdraw any non-Mechanicum forces from all of the Forge Worlds after the Emperor had been overthrown.

To allay the fabricator-general's misgivings, the Warmaster promised to provide the Mechanicum the lost secrets of ancient Standard Template Construct (STC) technology that had been recovered from the worlds of the recently subjugated Auretian Technocracy by the Warmaster's Sons of Horus Legion.

The fabricator-general was impressed with the Warmaster's gift, and admitted that it was a valuable STC database, but he wanted more. Regulus had anticipated this demand, and told Kelbor-Hal that the Warmaster promised to lift all restrictions on research into those technologies like Abominable Intelligence (A.I.) that the Emperor had declared forbidden.

To cement the alliance between the Mechanicum and the Warmaster and display the Traitors' seriousness about their cause, Horus had also provided Regulus with the security protocols required to unlock the infamous Vaults of Moravec.

The Vaults of Moravec were a repository of forbidden knowledge that the Emperor had ordered sealed two centuries earlier after the signing of the Treaty of Mars, for the vaults contained innumerable artefacts of technology that had been fashioned or corrupted by the malign power of Chaos, which were located under the Olympus Mons forge city.

Greedily, the fabricator-general struck the dark bargain, accepting Horus' proposal and willingly joined forces with the Warmaster, assisting the Traitors with all of the technology of Mankind at his disposal.

Schism of Mars[]

When the repository of the Vaults of Moravec was reopened, there was all manner of forbidden arcane knowledge and weaponry that had obviously been tainted by the corrupting influence of Chaos stored within.

Soon the corruption spread throughout the forges and temples to the Machine God across the Red Planet as "scrap code" -- Chaos-contaminated digital source code that was infected with an arcane computer virus -- infested the logi-stacks and cogitator (computer) archives of the Mechanicum, causing literal Chaos to emerge in any cogitator system that was networked to one of its infected counterparts.

It also caused reactors to melt-down, production lines to stop, and whole forges to cease production of weapons needed.

The opening acts of treachery had already occurred, yet the fabricator-general could not openly march to war against the Emperor without the appropriate pretense, providing the excuse to silence his detractors and eliminate his rivals. Kelbor-Hal and his allies amongst what would later be called the Dark Mechanicum used the disruption unleashed by the scrap code attack to bide their time and marshal the strength of their forces.

Kelbor-Hal and his allies also used the tactics of sabotage and assassination in an attempt to eliminate those who were unwilling to join their cause. But the opportunity to go openly to war eventually presented itself when the Techno-Magi Koriel Zeth, the Mistress of Magma City, declared that she did not believe the Omnissiah actually existed.

This open apostasy from the sacred doctrines of the Cult Mechanicus was the excuse the forces of the Dark Mechanicum needed to finally wage open warfare against their enemies, declaring them to be heretics and apostates to the faith that had been sacred on Mars for millennia. Magma City would soon become a focal point in the struggle for those amongst the Mechanicum who remained loyal to the Imperium.

Open warfare eventually erupted across the Red Planet as Martian forces, both civilian and military, fought one another in a deadly and escalating civil war whose destructiveness mirrored that unfolding in the wider galaxy between Loyalist and Traitor forces.

Acts of Treachery[]

Kelbor-Hal Post-Heresy 2

Kelbor-Hal, Traitor fabricator-general of Mars, overseeing the launch of the Furious Abyss.

To help the Warmaster achieve his goals, Kelbor-Hal oversaw the construction of the mighty battleship Furious Abyss in the orbital shipyard of Thule, a former asteroid, which had been towed by the Mechanicum into orbit of the gas giant of Jupiter in the Sol System, far beyond prying eyes and questions.

This formidable warship was unlike any other of its kind. It was so heavily armoured that it could withstand even a concerted assault from a planetary laser defence battery. It was the greatest and largest vessel ever assembled by Mankind, unique in every way and powerful beyond reckoning.

Kelbor-Hal had sanctioned the construction of such a vessel because it suited his great purpose, namely the burgeoning desire, or rather intrinsic programming, within the servants of the Machine God to gradually become one with their slumbering deity.

The Emperor had sought to place restrictions upon the Mechanicum's ability to explore every avenue of knowledge that might lead to a closer unity with the Machine God. Horus had promised to remove all of those restrictions and perhaps open even new vistas of knowledge for the Mechanicum to explore in the form of his allies amongst the entities of the Warp.

Faced with such a choice, the question of Kelbor-Hal's allegiance and that of the Mechanicum factions loyal to him had required mere nanoseconds of computation.

The Furious Abyss had been intended to become the new flagship of the traitorous Word Bearers Space Marine Legion. None could know of the vessel's existence until it was too late. Steps had been taken to ensure that remained the case. The massive battleship had been created with one deliberate mission in mind: the annihilation of an entire Space Marine Legion.

The Word Bearers' ultimate aim as part of the Warmaster's larger plan of conquest was to infiltrate the Realm of Ultramar in the Eastern Fringes of the galaxy and attempt to destroy the Ultramarines Legion and their homeworld of Macragge.

In a final act of treachery, Kelbor-Hal had the Jovian shipyards destroyed once the Furious Abyss was complete. There was no time to flee to safety for the workers at the yards and no survivors. Every tech-priest, servitor and menial present at the yards was burned to ash. None would discover the massive starship that had been fabricated upon the asteroid's surface until it was much, much too late.

A great deal of precious technology was lost during Thule's destruction and so it proved to be a steep price for the Traitor elements within the Mechanicum to pay for the absolute and certain secrecy required to bring to fruition the Warmaster's plan to destroy the Ultramarines. But in the end, the fabricator-general's will had been carried out and the Dark Mechanicum played its part in the tragedy that would ultimately unfold on a world called Calth.

Solar War[]

Following the Solar War, the Loyalist blockade of Mars was lifted and Kelbor-Hal was able to take direct command of the Dark Mechanicum war effort again.

Arrogant and preening in his self-importance, he attempted to take credit for many of the achievements of Perturabo and Sota-Nul against the defences of the Imperial Palace during the Siege of Terra.


After the Horus Heresy ended in a pyrrhic victory for the Imperium, the traitorous forces of Chaos that had served the Warmaster were driven towards the Eye of Terror during the brutal military campaigns remembered as the Great Scouring.

The Renegade tech-priests of the Dark Mechanicum were also driven from Mars by the resurgent Loyalists amongst the newborn Adeptus Mechanicus. These Renegades fled the Imperium into the far corners of the galaxy and some also took refuge in the Eye of Terror.

In exile, the Dark Mechanicum became even more enthralled to the power of the Warp and heretical technologies.

The ultimate fate of the traitorous Fabricator-General Kelbor-Hal in the final days of the Horus Heresy is unknown.



Warhammer 40,000 Grim Dark Lore Part 18 – Return to Terra


  • Battle for the Abyss (Novel) by Ben Counter
  • Mechanicum (Novel) by Graham McNeill
  • The Lost and the Damned (Novel) by Guy Haley, Ch. 17
  • The Horus Heresy: Collected Visions (Art Book), pp. 42, 266 (Images)
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Warhammer 40,000 Overview Grim Dark Lore Teaser TrailerPart 1: ExodusPart 2: The Golden AgePart 3: Old NightPart 4: Rise of the EmperorPart 5: UnityPart 6: Lords of MarsPart 7: The Machine GodPart 8: ImperiumPart 9: The Fall of the AeldariPart 10: Gods and DaemonsPart 11: Great Crusade BeginsPart 12: The Son of StrifePart 13: Lost and FoundPart 14: A Thousand SonsPart 15: Bearer of the WordPart 16: The Perfect CityPart 17: Triumph at UllanorPart 18: Return to TerraPart 19: Council of NikaeaPart 20: Serpent in the GardenPart 21: Horus FallingPart 22: TraitorsPart 23: Folly of MagnusPart 24: Dark GambitsPart 25: HeresyPart 26: Flight of the EisensteinPart 27: MassacrePart 28: Requiem for a DreamPart 29: The SiegePart 30: Imperium InvictusPart 31: The Age of RebirthPart 32: The Rise of AbaddonPart 33: Saints and BeastsPart 34: InterregnumPart 35: Age of ApostasyPart 36: The Great DevourerPart 37: The Time of EndingPart 38: The 13th Black CrusadePart 39: ResurrectionPart 40: Indomitus