I bought two Castellax off eBay in 2019 for a Zone Mortalis game that never happened. One turned up with a leg bent about fifteen degrees out of true, and I did the thing every forum tells you to do with warped resin, which is dunk it in hot water and bend it back. Water too hot, held too long, and that leg now has a flat spot shaped like my thumb. Both big lads are still boxed under my desk. I’d bought them off the back of a picture in an old Imperial Armour book, a bronze and green robot with circuit-work painted down its shoulder plates, and until this week I couldn’t have told you which forge world that livery belonged to.
It’s Zhao-Arkhad. Games Workshop ran the place this week as the newest entry in Pages from the Black Books, their series of free lore excerpts from the old Forge World Heresy hardbacks, following the Xana Incursion piece from the week before. This one pulls from 2016’s Book Seven: Inferno, the Burning of Prospero volume. The WarCom write-up runs about four paragraphs and finishes by pointing you at a Castellax-Achea kit, which is fine, that’s the job. Four paragraphs doesn’t leave room for the 013.M31 entry, which is the one I keep thinking about.
Everything on Zhao-Arkhad rusts
The colony started as a Mechanicum Ark out of Mars, sent in the late Age of Strife to spread the Machine God’s doctrines and then lost. Warp storms wrecked its drives and it fell out of the immaterium somewhere in the deep galactic south, around a white star with nothing charted for a long way in any direction. One green world in the system. The atmosphere is toxic to unaugmented humans because it carries too much oxygen for a human body to process, with humidity heavy enough on top of that to make breathing hard work. Rainforest canopy thick enough to hide macro-predators. The Titans escorting the colonists spent generations killing serpents and armoured insects before they ever fought anything that shot back, and those Titans became the Legio Xestobiax, the Iron Vigil.
The oxygen and the damp do something else. Metal corrodes on Zhao-Arkhad faster than anywhere else the Imperium keeps records for, so every forge-fane on the planet is subterranean and the working population lives on three lunar colonies instead of the surface. The planetary population is unusually low for a forge world because of it.
The Thousand Sons found them during the Great Crusade. Fifth Fellowship, per Inferno. Xenos raiders had been hitting Zhao-Arkhad for centuries, the XV Legion drove them off, and compliance happened without a shot fired between the two of them. Zhao-Arkhad supplied the Legion with war materiel from then on, under a treaty that included a Thousand Sons garrison stationed on the planet.
The Arkhadian forge on Prospero
WarCom compresses this into a line. The first Arkhadian shot of the civil war came from a satellite forge-fane the world had built on Prospero, thousands of light years from home, and it was fired when Leman Russ came down on the City of Light. The forge-fanes back on Zhao-Arkhad itself were still going about their business.
That sub-fane did well. Its void shield network plus the depth of the Prosperine soil carried it through the opening bombardment more or less intact, and when its small Legio Xestobiax garrison rose out of the subterranean bunkers it went toe to toe with a maniple of Legio Mortis and beat them. Book Seven makes a point of how badly that landed with the tacticians of the day, a minor Titan Legion from a backwater besting the most powerful Titan Legion of the Crusade era. The Ordo Sinister came in and destroyed the forge-fane afterwards, once the Mortis assault had failed.
For that, the entire homeworld was condemned. Guilty by association, in the actual phrasing. Every fane, every moon, every magos on a planet nobody had consulted, over the actions of a satellite operation on someone else’s world. It’s the corporate version of getting sacked because a branch office you have never visited failed a health inspection.
Condemned by a fleet that never showed up
The Mechanicum sent an inquisition and audit fleet to punish Zhao-Arkhad. It never arrived. The Heresy and the warp between them saw to that, and the world sat in a quadrant that saw none of the civil war’s major fighting.
The supreme-domini did declare for the Warmaster. Her own Purist faction deposed her and had her executed, a job made considerably easier by the Thousand Sons garrison having already packed up and left. After that there was no supreme-domini at all, because the remaining forge-domini couldn’t agree on one. Individual fanes declared independence, seized vessels and Navigators, and departed to secure their own supply lines. Some went mercenary, selling their services for raw materials and new technologies, and a few of those ended up working for Death Guard warbands. Others stayed put and either hoped the Imperium would put things back together or just wanted the galaxy to leave them alone. Paranoia set in and the internal purges started chewing through the thrall and worker population.
The Taghmata Kriarii spent all this fighting alongside the Raven Guard at Priam, far off in the galactic north, and didn’t learn their world had been censured for two full standard years. Two years. That’s about as long as I’ve had my Thousand Sons finished and still kept buying more of them.
013.M31
The account is a single timeline entry in White Dwarf #478, headed 013.M31: The Ghosts of Zhao-Arkhad, and it runs about three hundred words.
An impetuous contingent of the Ist Legion, riding the momentum of the Lion’s campaign, reaches Zhao-Arkhad and makes planetfall at its principal forge-fanes. Drop pods, orbital assault transports, the full Dark Angels production. And out of the psi-mists hanging over the forges come warriors in crimson armour. Thousand Sons. A Legion the Imperium believed Russ had finished at Prospero.
They don’t shoot. They proclaim loyalty to the Emperor and offer to parley.
The Dark Angels attack anyway. The Lion’s standing orders were to subjugate a traitor forge world, and the officers on the ground took the Prosperine warlocks for liars, which given the Legion and the decade is not an unreasonable read. What follows is three successive counter-assaults out of an ever-shrinking beachhead, none of which achieve their goals, against psychic power and a tide of battle-automata that WD #478 calls seemingly endless. Then the Xestobiax Titans come out of the ground. Hundreds of Loyalists die, the Ist Legion pulls back to its fleet, and the survivors sit in orbit enforcing a blockade while they wait for the Lion to tell them what to do next.
I saw a Xestobiax Reaver in a display cabinet at an event a couple of years back, purple and bone with the checked banners hanging off its shins, and I read the plaque twice because I’d never heard of them. The plaque didn’t mention Zhao-Arkhad either.
Were they lying
Probably, is my honest answer. Thousand Sons survivors turning up on a forge world their Legion held a standing treaty with, years after Prospero burned, claiming loyalty to the Emperor who ordered the burning, is not a claim I’d take at face value either. Magnus was on the Planet of the Sorcerers by then and Ahriman’s Rubric had already hollowed the Legion out. Whatever those ones were, they weren’t taking orders from any loyalist chain of command.
Then again, nobody checked. The Thousand Sons on Zhao-Arkhad did exactly one thing in that whole account, which was defend a forge world against an invasion, and the world they defended had already executed its own leader for siding with Horus. I keep going back and forth on it. The Dark Angels made the safe call, I’d probably have made the same call, and it still cost them hundreds of Astartes to learn nothing. Kiran reckons the entire episode reads like an Alpha Legion operation and I’ve stopped arguing with him about it.
The automata that did most of the killing are worth a look on their own terms. White Dwarf #419’s write-up of the Castellax-Achea describes a standard Castellax chassis fitted with forbidden sorceries so a Legion psychic adept can drive the thing like a puppet, with the cybernetica cortex in its chest replaced by “a strange crystalline array of troubling provenance.” That’s Mechanicum understatement doing a lot of heavy lifting. Half of them carry mauler-pattern bolt cannons and the rest carry aether-flame cannons, the same weapon the Legion’s warbands are still using ten thousand years later. Given that no two forge worlds agree on what animates a machine at the best of times, you can see why Mars took the view it did.
What Metalica found
The Imperium came back during the Great Scouring, this time with a warfleet out of Metalica, and this time it worked. Zhao-Arkhad was subdued, purged of its heretek beliefs and welcomed back into the fold. Between the war damage, its own purges and Metalica’s, the world that rejoined the Imperium was a fraction of what it had been, and rebuilding took centuries.
During that reclamation the Metalican assay teams found an STC database. The Crassus Armoured Assault Transport came out of it. So did the Praetor Armoured Assault Launcher and the Dominus Heavy Siege Bombard, patterns that had been written off as lost, and all three get built on forge worlds across the Imperium today. Zhao-Arkhad’s own manufactoria put the Praetor into production and it spread through frontline regiments across the Segmentum Tempestus.
The formal verdict on the world, once all of that was finished, was that it had been guilty by association. Zhao-Arkhad kept that classification through the purges, the occupation and the loss of the three templates.
There’s a line in Psychic Awakening: Ritual of the Damned, in the order of battle for the Upsilon-Kapha Severance, listing a heretek force of 1,200 macroclades called the True Believers of Zhao. I don’t know whether that’s Zhao-Arkhad or a coincidence of naming, and I’ve not found anything that settles it. The record itself says full analysis was impossible due to empyric disruption and contradicting reports, which is convenient for me and probably deliberate on someone’s part.
Zhao-Arkhad in the Era Indomitus is the foremost forge world in its segmentum, running grey and red heraldry and holding offworld enclaves as far out as Varangantua, where the locals call the compound Steelmound. Anyone there who publicly subscribes to Belisarius Cawl’s methods gets prosecuted as a heretek, on a planet whose entire historical problem was unorthodox technology. And at some point the Arkhadian authorities located a cache of Legio Xestobiax Titans that had been sealed away specifically because they contained eldar-derived heretek, and the ruling was to switch them back on.
