The Cult of the Bladed Cog is born as much of metal as it is of raw human stock, and is further augmented by the extra-galactic anatomies of the Tyranids. This great blend of human flesh, xenos beast and war machine is a deadly threat to its Adeptus Mechanicus hosts.
Feinminster Gamma was once a humble Imperial planet, its people often referring to it as "a cog in the great machine." Since its oppressed masses embraced new rulers from beyond the stars, that mantra has been abandoned, and the metaphorical cog turned into a weapon.
Feinminster Gamma is no longer an underappreciated component of a galaxy-spanning stellar empire, but instead the central hub of a new order -- one devoted to slaughter and destruction in the name of an uncaring xenos species.
In the late 41st Millennium, the macroclade army of Tech-priest Dominus Ovid Thrensiom -- who would become known as the "Great Miser" -- had arrived on Feinminster Gamma in force. To facilitate their mech-aquisitive crusade across the stars, and to refuel the Questor Mechanicus Knights that accompanied them, they sought resupply on a grand scale.
Yet the planet, despite their Tech-priests' assumptions, proved to have a remarkably low energy yield -- since the opening of a major Warp Storm in the neighbouring Vakadan System, many of Feinminster Gamma's meagre generatoriums had been running on emergency protocols simply to keep artificial lighting shining bright. The populace reasoned that if the baleful light of the empyric tempest was eclipsed by conventional lumen globes closer to home, none would stare too long at that celestial phenomenon, and hence countless citizens would be spared from madness and despair.
When Ovid Thrensiom found the paltry generatorium districts struggling even to keep the cities lit around the clock, his hopes of securing a forward base deeper into space were dashed. In consultation with his Fulgurite advisors, Thrensiom decided to take a rich harvest of bio-electricity from the planet's living population instead. The techno-census that followed, ostensibly levelled to catalogue those who had bionic enhancement and those who did not, instead saw tens of thousands of citizens leaving the halls of the Adeptus Mechanicus as stumbling, near-comatose husks.
Civil unrest fomented slowly, but bubbled to the surface as a powerful eruption that could not be denied. Using industrial tools, improvised weaponry and rudimentary guns purchased on the shadow markets, the slave workers of the planet Feinminster Gamma rose up against the agents of the Cult Mechanicus who had sought to bleed them dry. They were hopelessly outmatched.
Extermination Servitor details and Skitarii macroclades were sent to eradicate the worst of the slave revolts, though in his insatiable greed for more energy, Thrensiom spared the lives of as many people as he could -- and hence let the seeds of a new rebellion grow amidst the ashes. For a while, the Adeptus Mechanicus regained control, but the atmosphere of oppression and paranoia that resulted was fertile ground for the spread of an underground religion.
When in the midst of this political turmoil a Purestrain Genestealer was unwittingly borne to the planet's surface by the cargo freighter Redspark, a widespread cult of deliverance was soon to follow. The xenoform was seen as proof that there were other cultures, and even other intelligent species, beyond the clouds that were surely less cruel and tyrannical than the Adeptus Mechanicus. The crew of the Redspark were adamant that salvation could be found in the worship of their unusual cargo.
Slowly at first, but with gathering speed, whispers of a "New Deliverance" movement spread throughout the populace. No longer would the cultists be content to be part of the same heartless and unceasing machine as their rulers -- instead, they would become a blade. The code-brands and electoos with which the planet's Tech-priest overseers had marked their citizen workers were in many cases altered in illicit inker-dens to jibe with the new imagery of the emergent cult.
The Omnissiah's sacred Cog Mechanicum was adapted to better resemble the jag-spined emblem with which the creed marked out its faithful members. Slogan tattoos became common, worn across the collarbone or spine, each bearing a message that a believer in the Martian creed would consider shocking and blasphemous in the extreme. Every solar hour, the forge temples of Feinminster produced a new clutch of battle tanks and Servitor-pattern transports -- these too were taken by the cult and daubed with its rebellious insignia.
The common populace were not the only ones to fall under the spell of the Cult of the Bladed Cog. Though it took the mental onslaught of the Genestealer Patriarch itself to achieve it, many Skitarii were brought into the embrace of the cult. Their electro-spoor signatures and noospheric auras gained them entry into many areas that should have been forbidden, and allowed the cult to spread unchecked.
With these cyborg inductees gradually corrupting the brotherhood of their own clades, the seeds of the populace's grim salvation were sown. The day of ascension was triggered only when every parameter, run through exhaustive simulations by the former Skitarii Alpha who acted as the cult's Nexos, pointed towards victory. With mathematical precision, Thrensiom's electrophagic regime was overthrown, the Tech-priest himself slain by a Sanctus' biomutative bullet so the cult's nemesis could know the terrible glory of unbound flesh before he died.
On that day the broodkin of the Bladed Cog swapped one set of cruel masters for another -- though they are yet to learn that their new overlords ultimately answer to a force that is infinitely worse than that of their former rulers.
Where the Cult Mechanicus seeks to unite flesh with metal -- and in some cases, replace one with the other -- the Cult of the Bladed Cog seeks to blend the stuff of the alien with that of the machine. Cyborgised bodies are common in the varied ranks of the Bladed Cog, their tortured anatomies as much metal, wire and hydraulics as they are alien chitin and fused human bone. The bionic creatures that form the vanguard of each of the cult's uprisings are blasphemies against the Omnissiah so shocking that they can stop one of Mars' faithful Tech-Adepts or Battle Servitors in their tracks.
To truly blend one with another is an impossible goal, for the Tyranid is as alien and distant from the Holy Machine as it is possible to be. Yet that does not stop the Bladed Cog from pursuing their crazed agenda with the fervour of fanatics possessed of a new obsession. They depict their deity, the "Clawed Omnissiah," as having robotic pincers alongside the primary talon-limbs that would be familiar to any Ordo Xenos Inquisitor or Deathwatch Veteran.
Some go so far as to join their armaments with their own bodies, undergoing painful cybernetic implant surgery until they become one with their weaponry. Others begin life as dull-witted Servitors, given new direction by the hypnotic gaze of a Magus -- or even the Patriarch itself -- until their single-mindedness is turned towards destruction in the name of the cult.
The Xenos and the Beast
An infestation of the Rusted Claw finds it near impossible to move their Magus across the planet of Anacharos at anything faster than a walk. Their Magus' skin crawls with a high concentration of metallophage organisms, and any metal nearby instantly corrodes, rendering vehicles in his vicinity inoperable. Securing the aid of their allies in the Bladed Cog, they commission a succession of Departmento Munitorum crates made of plastic compounds that are just as hard as steel.
With these they are able to spread the war leaders of their cult from one planet to another. When their Primus, the resourceful Fender Threnn, hears word of a nest of Ferro-Beasts in the long-forsaken Yimbo System, he uses the same Munitorum crates to capture the armadillo-like metal-eating monsters by the dozen.
These he sets loose in the spaceports of Anacharos, causing utter havoc as the beasts go into a feeding frenzy amongst the richly appointed vessels. The distraction is used to full effect as the cult rises up against the rich upworlders -- who, when attempting to flee the planet, find many of their vessels already half-eaten.
The Ghoulwright War
The scions of the Bladed Cog, having thrown off their oppressors on Feinminster Gamma, take their crusade against the oppression of the Adeptus Mechanicus to a string of Forge Worlds across the system -- and to the Iron Hands Space Marines that the priests of Mars call their allies.
They propagate the belief that the Machine Cult is misleading the people of the Imperium by cleaving to the mantra that the flesh is weak, and those without access to cybernetic augmentation prove most receptive to the idea they too have intrinsic value. The Bladed Cog welcomes the flesh and blood as well as the cyborg, preaching that flesh is clay to be hardened in the kiln of war rather than replaced entirely.
In secret training camps they amass their armies of faith, equipping them with the finest wargear the Imperium can provide. When they strike against the Iron Hands of Clan Raukaan on the Forge World of Ghoulwright, the resultant techwar sees the planet consumed in the fires of battle.
- Codex: Genestealer Cults (8th Edition), pp. 24-25, 38-39
- Codex: Genestealer Cults (7th Edition), pp. 19, 48-49