Mondus Occulum, the jewel of the northern forges, most valued and most industrious of weapon shops. Greater even than the Olympica Fossae assembly yards, only Lukas Chrom's Mondus Gamma facilities replicated the work of the Fabricator Locum's mighty forge, but even his great forge could not match its output.

Covering hundreds of thousands of square kilometres between the domed mountains of Tharsis Tholus and Ceraunius Tholus, Kane's forge complex was a magnificent, monstrous hinterland of hive-smelteries, weapon shops, armouries, refineries, ore silos, fabrication hangars and industrial stacks.

Numerous sub-hives, Uranius, Rhabon and Labeatis being the greatest, towered over the production facilities, the sinks and towering hab blocks home to the millions of adepts, menials, labourers and muscle that drove the machines of the northern forge.

Like most forges of Mars, the iron-skinned manufactora of Mondus Gamma were geared for war. The conquest of the galaxy demanded weapons and ammunition in quantities unknown in earlier ages of the galaxy, and the hammer of beating iron and the milling of copper jackets was unceasing.

In the collapsed caldera of Uranius Patera, gigantic Tsiolkovsky towers lifted thousands of cargo containers from the supply yards into fat-bellied mass conveyers in geosynchronous orbit, ready to be transported to war zones flung out across the Imperium. Each tower was like an impossibly thick, pollarded tree, yet rendered slender by their height as they vanished into the poisonous, striated clouds that pressed down on the forge.

Both Mondus Occulum and Mondus Gamma in the south were facilities geared for war, but it was a specific branch of warriors to whom the industry of these forges was dedicated: the Astartes.

Crafted within these forges were the guns and blades wielded by the Emperor's most terrifying warriors in the prosecution of his grand dream, fabricated by the most skilled adepts and warranted never to fail by the Fabricator Locum himself. The battle plate of the Astartes was painstakingly wrought upon the anvils of master metal-smiths augmented with the highest specifications of manual dexterity and tolerances.

Boltguns, lascannons, missile launchers and every other weapon in the Astartes inventory was produced here, the martial power of the Legions first taking shape in the sweating, red-lit halls of Mondus Occulum. Armoured vehicles rumbled from assembly lines housed in vast, vaulted hangars and entire city-sized regions were dedicated to the production of unimaginable quantities of bolter ammunition.

But Mondus Occulum did not simply gird the Astartes for war with weapons and armour; it was also a place where minds were honed. Astartes warriors deemed to have an affinity with the mysteries of technology were permitted to study the ways of the machine under the tutelage of its master adepts. Fabricator Locum Kane himself had trained the finest of them: T'Kell of the Salamanders, Gebren of the Iron Hands and Polonin of the Ultramarines, warriors who would take what they had learned back to their Legions and instruct their neophytes.

Mondus Occulum, beloved of Mars, the jewel of the northern forges. Most valued and most industrious of weapon shops. Domain of the Fabricator Locum of Mars, the man second only to the ruler of Mars himself. And correctly one of the few forges of Mars to have avoided outright collapse.

Flanked by a chittering retinue of noospherically-modified servitors with blank, golden facemasks, harried calculus-logi and a number of specialised data scrubbers whose fear was evident in the harsh binary blurts of cant passing between them, Fabricator Locum Kane sought to stay calm by immersing himself in thoughts of the mundane as he passed beneath the gilded archway that led to the armourium.

Beyond his forge, events of a great and terrible nature were unfolding, but for now, for this moment, he concentrated on keeping the processes of his own forge working as normally as possible in the face of the devastation.

The cavernous chamber beyond the arch was brightly lit, its roof hundreds of metres above him and its far end lost to perspective. Loader servitors and whining elevators carried racks of Astartes battle plate, stacking them in metal-skinned containers arranged along the height of the walls and in long rows that stretched off into the distance.

Hundreds of quality-checking adepts moved through the chamber, hard-plugging in to each container and checking the measured readings of each suit of armour with previously inloaded specifications. Only rarely would armour produced at Mondus Occulum fail to meet Kane's necessarily high tolerances, an occasion that would result in a thorough investigation as to the cause of the defect. Such defects would not be replicated, and those whose laxity had allowed it in the first place would be punished.

Only once every suit had been checked and certified battle-ready would it be shipped to Uranius Patera and the orbital elevators. Warranted never to fail was a promise Fabricator Locum Kane took seriously, even now.

Especially now.

Kane took a deep breath, inhaling and sorting the chemical scent of the air before turning to his magos-apprenta. 'Can you smell that, Lachine?'

'Indeed, my lord,' replied Lachine, using his fleshvoice in emulation of his master. The boy's voice was nasal and unpleasant, and the sooner he was augmented with a vocaliser the better, thought Kane. 'Calcined aluminium oxide, a lapping powder that can reduce lapping and polishing time of armour by at least twenty per cent and which is particularly effective on hard materials, such as silicon and hardened steel. Also, microcrystalline wax and dilute acetic acid.'

Kane shook his head and placed a hand on Lachine's shoulder. The boy was much shorter than Kane and his demeanour entirely literal, a useful trait in an apprenta in terms of efficiency and work, but a frustrating one for conversation.

'No, Lachine, I mean what the smells represent.'

'Represent? Query: I do not understand your contention that odour is a signifier.'

'No? Then you are missing out, Lachine,' said Kane. 'You register the chemical components. I, on the other hand, register the emotional ones. To me, the gentle, reassuring smell of lapping powder, polish and oil represents stability and order, the certainty that we have played our part in ensuring that the Emperor's warriors are equipped for battle with the best armour and weapons we can provide.'

'I see, my lord,' said Lachine but Kane knew he did not.

'At times such as this, I find such things a comfort,' explained Kane. 'A great factory with the machinery all working and revolving with absolute and rhythmic regularity, and with its workers all driven by one impulse, and moving in unison as though a constituent part of the mighty machine, is one of the most inspiring examples of directed force the galaxy knows. I have rarely seen the face of an adept in the action of creation that was not fine, never one which was not earnest and impressive.'

Kane paused as a lifter-servitor passed, carrying a rack of gleaming, freshly-dipped suits of battle plate. The brutish monster was all muscles, pistons and gene-bulked torso, and it effortlessly bore the heavy weight of the armour in its hydraulically clawed fists. Each suit shone silver, the metal and ceramite unpainted and left for each Legion to adorn with its own colours.

'Like knights from a bygone age of Terra,' said Kane, setting off along the serried ranks of thousands upon thousands of suits of armour contained within the chamber. 'A byword for honour, duty and courage.'

'My lord?'

Kane gestured towards the armour with a dramatic sweep of his hand. 'This armour is a resource more precious than the wealth of worlds, Lachine. On most days it gives me great satisfaction to know how much the Astartes depend on us. I can normally lose myself in this place.'