Peeking around the fragment of wall, Atebe counted two infantry squads – seven personnel left, eight right – plus a five-strong command squad near the centre, spread out across the quadrangle.

  She put her crosshairs in the centre of the scarified eight-pointed star on the leader’s forehead and offered up a prayer to the God-Emperor. The traitor chieftain’s skull exploded in a red mist. He collapsed in a boneless heap as his squadmates dived back behind their Chimera for cover.

  The Chimera’s multi-laser and heavy bolter opened fire on Atebe’s position, pulverising her cover. She rolled left, tumbling back down the broken staircase and landing heavily on the rubble-strewn floor beside Traxel.

  ‘Nice shot,’ Bissot voxed appreciatively as the Chimera continued to pummel the second storey.

  Atebe chuckled, giddy from the Scholam’s Gift. Dopamine hummed in her brain’s reward centres as dust rained down on her. Simultaneously, a flood of endorphins pushed aside the pain that flared in her lower back from her bad landing. ‘Got me a bit more attention than I’d intended.’

  Below, Bissot fired a four-round burst at the Traitor Guardsmen nearest her. It was the best she could manage with her volley gun without risking a catastrophic overheat.

  ‘Praise the God-Emperor, Omnissiah and all the Imperial saints, it still fires!’ Bissot whispered over the vox. One of the Rilisians dropped, three shots stitching up his torso. His fellows opened fire on her position, forcing her to duck behind the shelter of a cratered wall.

  ‘Daviland, status with Phed?’ Traxel demanded.

  The first of the enemy’s combat vehicles ploughed headlong through the wall. Stone crumbled and steel shrieked as the Chimera thundered into the building. Two others followed. Behind them, two additional Chimeras bottlenecked the gaping hole in the wall. Guard troopers poured from transport bays, cutting off any chance at escape through the lower level as they swarmed the ground floor.

  ‘Ready, Tempestor,’ Phed replied.

  ‘Good,’ Traxel said. ‘Go.’

  Phed dropped from above, hotshot lasgun blazing automatic fire as he plunged into the mass of enemy troopers. Las-bolts flashed in the dust, blasting the Scion’s carapace armour open in a dozen places. Still firing, Phed collapsed into the rubble, brought down by a storm of las-rounds.

  Almost simultaneously, Phed detonated, the implanted dead man’s switch triggering the fifteen pounds of high explosives clustered about his body and obliterating the young Scion almost instantaneously. Those nearest the explosion were cut down by its force and the tempest of shrapnel hurled ahead of it. Cries of the wounded echoed through the roiling, choking cloud of dust left in its wake as the survivors scattered in blind panic, falling over one another in their haste to flee.

  ‘Kill everything,’ Traxel ordered. Chainsword revving, he dropped through the swirling dust into the crush of bloody, disoriented troops below.

  The eradicant complied without hesitation.

  XIII

  Water seeped down the rockcrete surfaces of the walls, glistening in the faint green light of the Scions’ slates monitron. It filled the network of tunnels beneath the academy, nearly knee-deep and rank with filth and the foetid remains of rat-gnawed corpses. It dripped from the ceilings, the faint splash of each droplet baffled and magnified by the claustrophobic confines to fill the entirety of the space with dribbling echoes.

  Norroll led, followed by Durlo, Fennech and Akraatumo, while Rybak covered the rear with his plasma gun. They slid like shadows, silent but for the hushed purling of their legs through the water. Their monoscopes remained dark. Trusting in their training to see them through the rambling, flooded warrens, the Scions relied upon their helms’ optics to pick up the faint reflection of their slates on the walls, portraying their surroundings in slightly hazy shades of green.

  The artillery battery lay above them to the south. Many passages had collapsed during the war, costing the Scions valuable time when they found themselves forced to double-back and find a new way through the flooded darkness.

  The enemy pursued them – they were certain of it. The sounds of seeping, dripping water masked their pursuers’ presence as surely as it camouflaged their own, just as the host of swimming rats and bountiful colonies of microbial life surrounding the putrefying bodies fouled Actis’ augurs.

  Lapping water echoed quietly from the walls, at one point far behind them, now maddeningly close at hand, its source ever obscure. A faint scraping of steel on rockcrete whispered from one of the many side offices or narthexes lining the corridors, though whatever had caused it vanished before the Scions could locate it. A slight disturbance in the buoyant filth skinning the water’s surface was the sole indication that anyone might have been there a moment before.

  Norroll glanced back over his shoulder past Durlo, to where Fennech moved at the centre of the squad. The commissar’s augmetic eye was almost dazzling in the darkness, bright like the first star in the evening sky. It illuminated his gaunt, lined face, rendering him in sputtering green light so that Norroll could plainly discern each detail of Fennech’s taut features. A grin spread across the commissar’s thin lips, growing broader with every strike and scrape that echoed from the shadows, seemingly entertained by the enemy’s ham-handed ­psychological games.

  Norroll drew a shuddering breath – the commissar’s display of grim amusement was far more disconcerting than the enemy’s clumsy intimidation attempts. He paused to collect his bearings, approximating where they were relative to where his internal compass told him the artillery lay.

  The scraping began again, echoing down a hallway to the right as they arrived at a four-way intersection, though once again they saw nothing more than disturbed flotsam bobbing on the water’s surface.

  Norroll turned right at the intersection, but the passage ahead lay blocked by rubble. Around the corner, at the rear of the formation, Rybak snarled in a combination of pain and anger. Norroll glanced back to find the gunner irately panning his plasma gun down the hall they had just come from, his respirator and optics hanging askew.

  ‘Rybak, shut up!’ Akraatumo hissed.

  ‘What happened?’ Norroll whispered.

  ‘Something opened my mask,’ Rybak said, fumbling to refit the respirator and optics one-handed. ‘I can’t see anything.’ He wiped blood from a deep laceration in the side of his face.

  The Scions’ formation collapsed in on itself, repositioning so that they had clear fields of fire down the hallway in three directions. Norroll and Durlo faced straight ahead and Fennech faced left, while Akraatumo faced rearward towards Rybak.

  ‘Akraatumo, help him get his mask and visor back on,’ Norroll said. ‘Any way to get us through this collapse?’ he asked Durlo.

  ‘Not unless you want me to bring down a lot more on top of us,’ Durlo replied.

  Norroll scowled. They were terribly exposed in the junction, and he wanted them moving again as quickly as possible. ‘Face about. If we go right at the next intersection, we should be able to–’

  A dull thump echoed down the corridor ahead of the commissar, followed by a wet snap as a bright light smacked off the corner just above Fennech’s left shoulder. The Scions reeled, momentarily blinded as their optics cut out to protect them from the glare. The magnesium flare splashed into the centre of the intersection, hissing and sizzling as it bobbed white-hot upon the surface.

  The water in front of Rybak exploded, a flash of speed and motion lunging at the gunner as an attacker burst from beneath the surface of the foul murk. Rybak fired, his cry of rage transformed into a gurgling hiss as a wickedly serrated flensing blade was buried to the hilt in his throat below the chin. Plasma detonated against the opposite wall as Rybak collapsed, splashing backwards as the momentum of his killer’s attack carried them both into the water.

  The attacker was up in an instant, blades flashing like quick­silver as he pistoned into Akraatumo. Even blinded, the vox-operator was far from defenceless – all the Scions had been trained in blind fighting since childhood, forced to overcome murder-servitors and teams of bloody-minded penal legionaries alike in the darkened caverns beneath Abstinax. Though the traitor had surprise and disorientation on his side when he attacked Rybak, Akraatumo had more than enough time to react to his follow-up. The butt of Akraatumo’s lasgun struck out like a staff, catching the wretched attacker in the mouth. The assassin’s jaw shattered, sending him crashing back into the wall, spitting blood and teeth.

  Las-fire streaked from the darkness in all directions, flashing with incandescent fury as it sparked from the Scions’ armour. The enemy had managed to get around them, using their native familiarity with the catacombs to trap the eradicant in a T-shaped kill-zone, doubtless expecting to make short work of their trapped foes.

  ‘Die in pain, apostates!’ Fennech shouted as he charged the Traitor Guardsmen ahead of him, las-fire fizzing from his carapace armour and refractor field. His bolt pistol flashed, rocket-propelled rounds penetrating flak armour to burst in plumes of flame and clouds of blood. Lightning rippled across his power fist as he swung it at a trooper with a vox-set. The oversized gauntlet struck the man in the sternum, sending chunks of flesh, bone and shattered armour exploding back into the hallway with a resounding crash.

  Durlo and Akraatumo leapt after the commissar, cutting apart the traitor Rilisians beneath a stream of rapid-fired hotshot rounds as they raked their lasguns down the length of the corridor on either side. Behind them, Norroll tossed a frag grenade into the passage to his right, sending the Traitor Guardsmen scrambling for cover in the seconds before it exploded.

  Norroll swayed sideways, instinctively dodging as a blade flashed a hair’s breadth from his throat. Rybak’s killer was somehow back on his feet, drooling blood from his mauled jaw. His dual blades hissed through the air beneath Norroll’s chin before he danced back out of the recon trooper’s reach. Norroll lunged forward, feinting with his own blades, and elbowed his assailant in the face.

  Knives clashed in the darkened corridor. Norroll managed to turn aside most of his opponent’s onslaught, but what the Guardsman lacked in skill he more than equalled with sheer, bloody-minded intent. The vicious abandon of his attacks forced Norroll back towards the intersection and into the enemy’s line of fire. Norroll jabbed with his right blade, then feinted left, noting the utter, desperate focus with which the traitor knife-fighter’s attention flickered between his flashing monoblades.

  Only the monoblades, though. Norroll blocked a brutal downward sweep, redirecting the energy into a riposte that cost the Guardsman half a step backwards. His enemy off balance, Norroll reversed the grip on his left blade and flipped it into the air above his opponent’s head.

  The Guardsman’s eyes followed the blade up, and in the infini­tesimal space of time between action and realisation, the Scion’s empty left fist ploughed into his already shattered jaw.

  Staggering backwards, the flenser’s eyes went wide in momentary confusion as Norroll stabbed him beneath the chin in answer for Rybak’s death, then deftly snatched his second monoblade as it fell.

  Norroll was already moving as las-fire strobed from the tunnel network behind him, sheathing his second blade to draw his laspistol. Ducking low, he fired three shots in quick succession, caring little whether they struck true, so long as they gave the enemy pause. Brilliant flashes of light stuttered across the darkness ahead, flaring from the water-soaked walls as the eradicant and the enemy exchanged fire in the next junction. Water splashed around his knees as he ran, dragging at his already sodden boots. He willed aside exhaustion and pain, ignoring the screaming cramps seizing his calves and shins that would drop an ordinary man – such weaknesses were beneath one of the God-Emperor’s Scions, and Norroll would sooner die than be overcome by mortal frailty. Teeth clenched, he pushed forward, water frothing as he sprinted down the corridor towards the flickering darkness.

  Las-bolts streaked over his shoulder, Akraatumo’s precision fire crackling past Norroll to bring down another of the traitors. A grenade burst down the corridor to his right as Norroll found his squadmates hunkering at the next junction. Durlo and Fennech poured fire into the corridor to either side of the intersection as Akraatumo shot over Norroll’s head, covering the rear.

  Bolt pistol empty, Fennech had drawn his holdout laspistol, though the weapon’s ammunition counter already blinked amber. Norroll sloshed to a halt next to the commissar and offered him a fully charged powercell, which Fennech accepted with a quick nod.

  Fennech ducked back around the corner as a salvo peppered the rockcrete wall. ‘I was hoping you’d catch up,’ he said. Blood dribbled from a fresh gash in his chin, though the old commissar seemed not the least perturbed by their situation.

  ‘We need to break through this intersection and head right,’ Norroll said, firing over Fennech’s shoulder. A wild-eyed trooper in hastily patched flak armour, draped in some manner of pelt, splashed down into the mire with a smoking crater in his chest.

  ‘Right seems to be where most of them are,’ Durlo said. ‘They knew which way we were going when they cut us off.’

  ‘They’re infidels, Trooper Durlo, not imbeciles,’ Fennech chided. ‘Though they have been perverted by the wiles of the Archenemy, they still retain the gifts the God-Emperor bestowed upon them, much like their Traitor Astartes masters.’

  ‘I’m all for suggestions that will take us out of this,’ Akraatumo said. He lay prone in the water, firing down the corridor behind them. A plasma bolt hissed over his head, streaking between Norroll and Durlo and bursting on the wall opposite.

  ‘We’re an eradicant,’ Norroll said. ‘Kill everything, figure out the rest after.’

  Fennech grinned, baring his teeth. It was the first time Norroll had ever seen a smile reach the old commissar’s good eye.

  ‘Akraatumo, keep doing what you’re doing,’ Norroll ordered. ‘Maybe try to kill the bastard who nicked Rybak’s plasma gun. Commissar, head left. Durlo, follow me right on my mark.’

  ‘Right with you, boss,’ Durlo said.

  Considering their circumstances, things were going better than expected.

  Norroll had no idea how many traitors they had encountered in the catacombs – the darkness, close confines and mutable kinetics of the battleground were mercilessly unquantifiable. He had stopped attempting to hold the eradicant to any route or direction. He had likewise ceased any real notion of rational thought, abandoning all pretence of strategy or higher reasoning for the simple, mechanistic process of killing.

  He had fallen into a dissociative hypomnesia, observing his own actions in some externalised, depersonalised manner in much the same way as he did his squadmates’. Blood sprayed from opened flesh and severed limbs as his blades cut, stabbed and parried, executing those three basic actions with the infinite variance dictated by the needs of the instant. There were times when he found himself marvelling at the simple efficiency with which the blades killed, before realising again that his own hands wielded them.

  Commissar Fennech, Durlo and Akraatumo fought with the same unconscious efficacy as he did, any semblance of artistry eliminated in favour of simple, economical butchery. Whether by gun butt, blade or power fist, the eradicant epitomised its purpose as an agent of eradication. This was not battle the Scions engaged in; it wasn’t even murder. Either abstraction required an emotional impetus, and the Scions fought with none, slaughtering the enemy with all the passion of abattoir servitors. The calculus of the situation had been gelled down into a simple binary equation: if the enemy came near, the enemy died.

  In the confines of the meat grinder that had become the entirety of their world, the eradicant resorted to close-quarters fighting. Fennech deflected a power axe with his sword, the weapons sparking as their crackling energy fields repelled one another, before sending his power fist crashing through his opponent to paint the walls with ruptured viscera. Back to back with the commissar, Durlo used his lasgun as a staff, blocking attacks and cracking bone with savage counterstrikes to vulnerable, unarmoured areas. Slightly removed from the rest of the group, Akraatumo carved through the Traitor Guardsmen with his Scion blade. He engaged a group of traitors simultaneously, using a sequence of quick strikes to sever tendons and open veins, crippling one opponent seconds before dispatching another with the dagger.

  Commissar Fennech had not been wrong – their foes were veteran soldiers. Trained and battle-hardened, the Rilisian Guardsmen had passed through a hellish crucible before their arrival at this moment. Despite their maddened glares and their scarified flesh, they remained a disciplined, well-drilled force.

  They were as children to the Scions of Abstinax. Though they were biologically human, the doctrine by which the Tempestus Scions were raised had transformed them into something else entirely. Punishingly extensive developmental regimes and intensive programmes of psychobehavioural indoctrination had effectively divorced them from their parent species, leaving only the most vestigial elements of humanity clinging to them. Trained to physical perfection, mentally reconditioned to be ignorant of pain and fear and single-mindedly deadly, the Scions operated at a level so far beyond their opponents that their combat prowess might as well have been supernatural.

  At range or close quarters, the expression of war was their language, for they fought and killed with the habitual fluidity of conversation. Akraatumo and Durlo attacked with effortless fluency, each strike, dodge and parry delivered with the easy aplomb of a seasoned debater arguing with children. In the elocution of war, however, Norroll and Fennech were master orators, each naturally gifted beyond native articulacy. Both were able to weigh the hostile crowd and convey an appropriate response – Fennech’s audacious and brutally forthright expression complemented the canny foresight of Norroll’s own discourse.