‘Have Squad Secundus fall back to the hold point on the floor above, they’re about to be cut off,’ Dantioch ordered.

While Adamantiphracts lanced the long corridor approach to the blockhouse with broad-beam las-fire from the flared barrels of their carbines, the ranking Angeloi Adamantiphact officer in the blockhouse – Lieutenant Cristofori – carried a useless, mangled arm in a sling and doubled as Dantioch’s tactical and communications dispatch. Operating a small but robust vox-bank, set in the embrasure wall, Cristofori was the Warsmith’s eyes and ears about the Schadenhold. While the lieutenant conveyed the order through a bulky vox-receiver, he filtered the flood of reports coming in from the vox-links of individual Iron Warriors and the comms stations of different blockhouses. Replacing the receiver, he put a finger to his headset and nodded.

‘Sir, Nine-Thirteen reports enemy reinforcements on the hangar deck,’ the lieutenant relayed.

‘Legiones Astartes?’ Dantioch asked. It would be hard to believe. If the bodies were anything to go by, Krendl must have committed a full demi-Grand Company by now. The Schadenhold was swarming with Perturabo’s progeny.

‘Imperial Army, my lord. Looks like foot contingents of the Bi-Nyssal Equerries.’

Dantioch allowed himself a hidden smile. New blood. It seemed that Krendl had been reinforced. This both pleased and vexed the Warsmith. Krendl had been sent to acquire reinforcements for the primarch and Horus Lupercal, not expend the Warmaster’s valuable manpower. That would be embarrassing enough. The problem with reinforcement was that it meant that Krendl had been outfitted to see the siege through to the end. Horus could not allow word of Lesser Damantyne’s resistance and the loyalty of the Iron Warriors to reach other Legions. The end was near.

‘Nine-Thirteen have been forced back to the fuel depot. Awaiting orders,’ Cristofori added.

Dantioch grunted. ‘Tell the ranking wardsman that he has permission to use the Nine-Thirteen’s remaining detonators on the promethium tanks.’ The Warsmith slashed a cross through the Schadenhold’s Stormbird hangars on the floor schematic. ‘We won’t be needing them. Let’s deny our enemy also. Nine-Thirteen can fall back by squads to this maintenance opening,’ he continued, stabbing the quill point through the vellum. ‘Then on to Sergeant Asquetal in the North-IV blockhouse.’

‘Sir, also – blockhouses South-II and East-III report dwindling supplies of ammunition.’

‘Collapse all of our people on levels two and three back to Colonel Kruishank’s hold point in the Hub,’ Dantioch grizzled above the gunfire.

‘The colonel’s dead, sir.’

‘What?’

‘Colonel Kruishank is dead, sir.’

‘Then Captain Galliop, damn it! They still have some limited supplies.’

‘Yes, my lord,’ Cristofori said unfazed and began relating the Warsmith’s orders.

This had been the order of things for as long as the Schadenholders could remember: battle coordinated a hair’s breadth under the fury of boltfire. Whereas the elevated embrasure was intended to provide space for such luxury, below on the chamber floor, Iron Warriors, Adamantiphracts and gene-stock ogres fought with adrenaline-fuelled frenzy. Each knew that his life depended upon the relentless taking of others and nowhere was this more evident than at the gauntlet-entrance to the blockhouse. The walls about the opening had lost their angularity and harsh edges. The perpetual assault of bolt-rounds and las-fire had chewed up the stone and returned the entrance to the rocky, cavernous irregularity of the cave system beyond. From the ceiling rained the gore of those who had failed to breach the chamber; the floor underneath was a mound of gunfire-shredded bodies and trampled armour.

At the centre of the blockhouse stood the Venerable Vastopol. The Dreadnought was too large to take advantage of much of the architectural cover and instead had stood its ground like a machine possessed, hammering anything advancing with the glowing barrels of its raging autocannons. The war machine had borne the brunt of the blockhouse defence; however, the reinforced plate of its sarcophagus body was a sizzling, bolt-punctured mess. The monstrous machine stood in a pool of its own hydraulic fluid and showered sparks from one of its clunky legs. The muzzle of its lower cannon barrel had been shorn off and the mangled chainfist bayonet below hung in a serrated tangle. About the Dreadnought, firing from loopholes and crescent alcoves in merlon walls, were its superhuman kindred. Experts in the art of encumbrance, the Legiones Astartes prided themselves on their beleaguered worth: every defending Iron Warrior had to slay so many of his traitor brothers in order to satisfy the Warsmith’s equations: algebraic notations calculated in time and blood.

‘Missile launcher!’ Tarrasch yelled from the chamber floor. As Legiones Astartes and Adamantiphracts retracted barrels and slammed their backs into protective scenery, the warhead rocketed up the passage and into the blockhouse. Striking a merlon wall the missile exploded, showering razor frag across the heads of hidden defenders.

Angeloi Adamantiphract marksmanship seared the length of the approach, hammering the plate of storming Iron Warriors and cutting up their Imperial Army opposites, las-fodder from the Expeditionary Fleet’s Nadir-Maru 4th Juntarians. Those that made the gauntlet-entrance faced a storm of their own: disciplined, ammunition-conserving blasts from the barrels of garrison battle-brothers. Armoured Legiones Astartes besiegers who breached the chamber dived out of the path of withering autocannon fire and las-streams and peeled off left and right, desperate for cover. Their desire to establish a foothold in the blockhouse took them straight into the reach of the Iron Palatine and his assault troops.

The Sons of Dantioch, scarred genebred hulks, pumped to obscenity with hormones and fervent loyalty, came at the interlopers with the mammoth tools of their trade – diamantine-tip hammers, serrated shovels and clawpicks. If that wasn’t enough of a nightmare for the blockhouse breachers, the Iron Palatine, Chaplain Zhnev and the Ultramarine Tauro Nicodemus were leading the charge.

An Iron Warrior invader broke from a cannon-mauled throng, a yellow and black-striped blur. With his Mark-IV plate alive with ricochets, the brute pushed himself away from one wall and then the other before tumbling into a messy roll. He was followed by two other traitors who blazed away with their bolters and a trail of opportunistic Nadir-Maru 4th Juntarians.

Genebred hulks descended upon the spearheading Space Marine, their picks and shovels sparking off his savaged ceramite. The second turned his wild bolter straight on Nicodemus, the azure glint of the Ultramarine’s armour instantly attracting the warrior’s attention. Zhnev wasted no time with the third, firing the pistons in his replacement shoulder. His hammer-fashioned crozius arcanum swung through the air in an unpredictable, pendula-jointed arc, crashing past the Iron Warrior’s helmet. Cleaving through armour plating and bone where the Space Marine’s neck met his shoulder, the Iron Warrior Chaplain fired his pistons again, swiftly retracting the sacred relic. Spinning with the pendula motion of the crozius, Zhnev howled his fury before striking the heretic’s helmet from his body.

Tarrasch plugged the resulting bloodhaze with alternate rounds from each of his bolt pistols, cutting down the Nadir-Maru troopers streaming in through the gauntlet-entrance. Dark, shiny faces beneath extravagant turbans bared bleach-white teeth at the Iron Palatine. The former Iron Warrior captain barked directions to the Angeloi Adamantiphract warriors at the embrasure walls and the Sons of Dantioch below to bring down the Juntarians in their own inimical ways.

With an enemy Legiones Astartes pounding across the killing ground at him, Brother Nicodemus of Ultramar took several practice sweeps with the gleaming blade of his gladius. On his other arm he supported the weight of a huge storm shield. The shield was as tall as the Ultramarine – a sub-rectangular plate, the curved, semi-cylindrical surface of which crackled with a protective energy field. The champion clutched it to his side like an airlock bulkhead.