It was located in the Golgotha Sector of the Ultima Segmentum perilously close to the permanent Warp Storm known as the Maelstrom. During the Age of Strife this Forge World was forced to survive the horrors of Old Night without the assistance of Mars.
The Mechanicum of Sarum eventually formed an aberrant order of machine Adepts known as the Redjak Cult. With their technological sophistication and mechanical prowess, the Sarum Mechanicum easily commanded control over most of the Golgothan Sector by the late 30th Millennium.
However, when Sarum faced a massive invasion by the Abhuman Brotherhood of Ruin and their Ork allies, the Tech-priests of that world pleaded for aid from the Imperium of Man's Great Crusade and finally received it in the form of the 13th Expeditionary Fleet of the World Eaters Legion, led personally by the Primarch Angron.
In the ensuing Imperial campaign that became known as the Golgothan Slaughter, the Brotherhood of Ruin and their Ork mercenaries were annihilated by the World Eaters. The Redjak Mechanicum were grateful to their saviours and pledged their undying loyalty to the XII Legion.
However, Angron eventually turned his wrath on the Crimson Priests of Sarum, scouring the planet and claiming it as his forward operating base for the next eleven standard years in a campaign against the Crimson Priests' own remaining empire in the sector. Of course, they were no longer in any position to complain about their loss of power to the Imperium that had saved them.
Eventually, the machine realm of Sarum, which had become a full-fledged Hell-Forge of the Dark Mechanicum, was subjected to some unknown Warp phenomenon that caused it to manifest at different times and places across the Golgothan Wastes and potentially beyond.
For millennia, tales of a wandering planetoid that is home to a crimson-clad order of hell-smiths has continued to permeate the legends of the void clans throughout the Golthan Wastes.
Like many Forge Worlds, the early history of Sarum has been lost during the long millennia. Sarum was a barren planet that lacked an atmosphere but was still home to extensive manufacturing facilities controlled by the Mechanicum. During the Age of Strife, the world was settled by the Mechanicum and transformed into an outpost of the Priesthood of Mars, but the station's Tech-priests soon found themselves isolated and embattled by the inhabitants of the Maelstrom.
On its own against raiders, xenos, and Abhumans and without aid from Mars, the Tech-priests of Sarum became isolationists and founded a deviant cult of the Machine God under the leadership of the Magos Redjak. Redjak solidified his so-called Crimson Priesthood's power over Sarum and used the technological prowess of the Mechanicum that he commanded to gain political control over much of the Golgothan Sector by the end of the 30th Millennium.
The Bloody Thirteenth
The first known target to suffer the wrath of the World Eaters Legion after their Primarch Angron took command of the XII Legion, sometime in the last two centuries of the 30th Millennium, was the stellar wasteland of the Golgothan Sector. The Golgothan Sector was sited near the galactic core in the Segmentum Ultima close to the realspace Warp rift known simply as the Maelstrom.
The breaking of the Siege of Sarum would soon become a cornerstone of the World Eaters' legend and serve as a portent of the dark path yet to come. Driving his Navigators perilously close to destruction in the Warp, Angron ordered his warships to form a single strike force aimed at the Sarum System. They came upon the besieged Mechanicum station world of Sarum on the edge of the Maelstrom, founded during the Age of Strife and long cut off from aid. Sarum was being besieged by the Abhuman empire known as the Brotherhood of Ruin who wished to take the Mechanicum's technological secrets for themselves.
The Tech-priests of the Mechanicum's Redjak Cult had endured alone for ages, subjected to the privations of raiders and enemies all around them, with only intermittent contact with distant Mars and the Forge World Anvilus, requesting aid that had never yet managed to reach them. The World Eaters arrived as their saviours, smashing into the heart of the besiegers. Though dramatically outnumbered and outgunned, the World Eaters drew into close formation and ripped through the enemy armada.
Once the enemy line of defence was breached, the World Eaters' fleet unleashed swarms of gunships and Drop Pods upon the planet's surface. In the meantime, baying for blood, Angron and his World Eaters ravaged the enemy armada, plunging in close so that the wild fire of their foes struck their own ships as often as those of the Imperials. Boarding Torpedoes and assault rams screamed out from the World Eaters' vessels and slammed into the hulls of terror ships and Abhuman vessels, disgorging the World Eaters in their unstoppable, inhuman rage, turning the enemy ships into charnel houses.
Meanwhile, on the surface below, Abhuman cyborg troops and their Ork mercenary lackeys died by the thousands, unable to coordinate a defence against this unforeseen direction of attack. The battle raged on for solar hours, and the World Eaters took horrific casualties but fought on nevertheless. The Abhuman warlords sensed at last that the battle was turning in their favour and called upon reinforcements from across the planetoid's surface to aid them.
It was then that a false dawn flared blood-red in the skies above. Seconds later, a Cyclonic Torpedo barrage smashed into the surface all around the World Eaters, who fought on. In their wake came hundreds of gunships and assault rams that represented the World Eaters' second wave, led by Angron himself. These warriors descended upon the Brotherhood of Ruin like a god of wrath. Behind them came seventeen great black metallic cylinders which disgorged the towering Titans of the Legio Audax, which strode forth, weapons blazing.
Seeing the shadow of the Omnissiah's wrath descending, the Redjak Mechanicum emerged from their fortifications and speared the fleeing enemy with barbed harpoons and dragged them back for their masters to rend. The Siege of Sarum had been broken and the Redjak Mechanicum swore to Angron and his Legion directly many oaths of fealty and entered pacts of mutual protection and support.
This provided the World Eaters and their Techmarines with a ready source of resupply and armament far outside the Imperium's inner sphere. The campaign that was to follow would last eleven standard years and see no fewer than 48 worlds and outposts ravaged and destroyed by the World Eaters. Seven separate dangerous xenos species were rendered extinct as the XIIth Legion's fleet cut a swathe of destruction through the wastes of Golgotha, and even ventured into the perilous fringes of the Maelstrom itself.
Of course, this campaign also destroyed the miniature stellar empire that the Crimson Priesthood of Sarum had established in the sector, but they were no longer in any position to gainsay the Imperium that had saved them from destruction.
The Daemon Within
During the final days of the Horus Heresy, the Primarch Perturabo of the Iron Warriors was sent to find Angron and bring both his Iron Warriors and the World Eaters Legions to the Traitor Legions' muster at Ullanor, so that the final assault on Terra could begin.
Knowing that the Tech-priests of Sarum supplied the World Eaters with much of their wargear, Perturabo set course for that planet to ask for news of his brother's whereabouts. When the Iron Warriors arrived in orbit of Sarum, they found the planet sheathed in debris.
Descending onto the surface, Perturabo and his retinue were led deeper and deeper into the heart of the Forge World. There they found a Warp entity bound to the core of the planet. This being was the daemon of Khorne named Sa'ra'am who claimed to have come into existence at the moment the first weapon made by a mortal to take a life was forged. Being confined to the heart of the Forge World was a fate the daemon secretly relished, as this fate meant it was free from the direct control of the Chaos Gods and no longer had to serve their every whim.
Perturabo threatened to free the daemon if it did not reveal the whereabouts of Angron. The daemon acquiesced and revealed that Angron could be found on the world of Deluge. The daemon then possessed the Iron Warrior Volk. Volk was the former commander of the 786th Grand Flight, a Lightning Crow pilot who had most of his body rebuilt and housed within a suit of modified Tactical Dreadnought Armour after being shot down in an engagement.
Several of the accounts of the Great Crusade that the Inquisition has unique access to make mention of the machine domain of Sarum, though they provide scant details save that the airless planetoid was home to an aberrant order of machine adepts and was the site of an overwhelming assault by the World Eaters Legion of the Legiones Astartes.
Having collated numerous texts on the subject of this world, Inquisitorial savants have uncovered a link between it and a number of void clanner legends long told throughout the Golgothan Wastes. Though each story differs in many regards, they all appear to describe a wandering planetoid which is home to a crimson-clad order of hell-smiths whose faces are dominated by lamprey maws lined with razor-sharp steel teeth. It is not known if the long-lost machine realm of Sarum was subjected to some unknown Warp phenomenon that has caused it to manifest at different times and places across the Golgothan Wastes and potentially beyond.
While outlandish, such events are far from unknown to the Inquisition. Furthermore, the savants of the Inquisition have assayed tales that the Heretic Astartes of the Warp Ghosts are able to predict or even cause manifestations of this ethereal Hell-Forge, acting as some form of dread ferrymen as they steer the long-damned foundries across the wastes and bring death and destruction upon the heads of those who dwell near the void along the coreward borders of the Segmentum Solar.
- The Martyred Sons (416.M37) - Inquisitor-Lord Antonius Coil of the Ordo Malleus discovered the current location of the nomadic Hell-Forge of Sarum while conducting an Exterminatus against the Warp-tainted Hive Worlds of Goleonda IX, and moved to see it destroyed at last. Along with warships committed from Battlefleet Reductus and several Militarum Tempestus regiments, he mobilised the aid of three Space Marine Chapters, the Brazen Claws, the Sons of the Raven and the Celestial Guard, to strike deep into the perilous Golgotha Wastes against this nightmarish thorn in the Imperium's side. Within sight of the baleful world, the Imperial fleet was ambushed on all sides by the pale warships of the Warp Ghosts and Black Wings Chaos Space Marines and the horrific Daemon Engines of their Dark Mechanicus allies of Sarum. In the brutal seventeen-solar-hour void battle which followed, the Imperial fleet was encircled and slowly torn to pieces both from without and from within as daemons ripped open passages into realspace deep aboard the stalwart vessels. Only the Chapter fleet of the Brazen Claws broke free from the trap without crippling losses, while the human contingent of the Imperium's strike forces was annihilated to the last. The ravaged Celestial Guard Chapter would take nearly a standard century to rebuild its grievous losses from its stores of gene-seed, swearing bitter vengeance against the Warp Ghosts. The fleet-based Sons of the Raven Chapter, not one of whose Astartes escaped the deadly trap, was declared martyred and the great Bell of Lost Souls in the Tower of Heroes on Terra tolled to mourn their passing. Eighteen standard years later, a corrupted Warspite-class Battle Barge, believed once to have been the Seraphina Carricus of the Sons of the Raven Chapter, was encountered transporting a Warp Ghosts raiding force off Mezoa XV, the withered face of Jo'sun Hernezu the martyred Chapter's last Master, worn by its revenant captain.
Like many of their Dark Mechanicum counterparts, it is suspected that the rogue Hell-Forge of Sarum is able to produce several vehicles, including the Thunderhawk gunship, by combining several different marks of Mars Pattern vehicles in a manner that no adherent of the Cult Mechanicus would countenance.
The Dark Mechanicum has melded corrupted machine rites with fell daemonological rituals to infuse the product of their labours with the power of the Warp. It is said by some that these Thunderhawks soar out of the soul-forges that spawn them in mockery of the noble phoenix of ancient Terran legend, their birthing-cries slaying hundreds of the forge-slaves who helped create them.
It is also surmised by the savants of the Ordo Malleus that the massive, gore-splattering Daemon Engines known as Blood Slaughterers are constructed, or otherwise called into being, by the artifice of the Dark Magi of the Hell-Forge of Sarum -- the source of the legend of the "Killing Star."
When the Killing Star appears in the night, it is not long before bloody red contrails slash across the skies and soon the horizon burns with distant fires. When the hosts of the Killing Star descend upon a world to shed blood in honour of the Ruinous Powers, they are often presaged by a wave of Blood Slaughterers, their serrated blade-arms gleaming in anticipation of the lives soon to be claimed.
These Daemon Engines bear a clear resemblance to the Greater Brass Scorpions of Khorne, yet Inquisitors and savants know not to rely on mere appearances when attempting to comprehend anything about the workings of Chaos.
- Codex: Adeptus Mechanicus - Skitarii (7th Edition), "Bastions of the Machine God," pg. 18
- Imperial Armour Volume Thirteen: War Machines of the Lost and the Damned, pp. 13, 22, 78, 121
- The Horus Heresy - Book One: Betrayal (Forge World Series), by Alan Bligh, pp. 99-101
- Slaves to Darkness (Novel) by John French, Chs. 12-13