'Quickly,' barked Tchure, urging them on through the flames and the smoke. At any moment, Marduk expected to be cut down by bolter fire, or for Guilliman to fall upon them, tearing them apart with his bare hands.

Kor Phaeron was gurgling and gasping, eyes rolling in their sockets. He clutched at Marduk, clinging to his robe with an emaciated claw. His eyes bled tainted darkness, burning with a fiery intensity even now.

He should be dead.

In the void where his primary heart should have been, instead a vile blackness roiled, wriggling like a pseudopod. Oily darkness coursed through Kor Phaeron's veins and arteries, spurting from where they were ruptured and severed and dissipating into the foul air. His ravaged flesh stank of dead meat and spent batteries.

Kor Phaeron writhed. Was this was the power that he had desired?

Sorot Tchure raised his left wrist. 'Get us out of here,' he growled into the Octed-inscribed glass blister embedded in his vambrace. The glistening, unliving thing within squirmed as it relayed his order.

The Ultramarines were coming for them, determined to cut off their escape.

Marduk saw his own death written in the eyes of the red-helmed swordsman and his fellows. He would not be able to avoid it.

The flames of the brazier seemed to dim, and the temperature dropped. Hoarfrost crept across the walls. The darkness itself began to move, writhing and growing.

Tendrils of shadow reached out, groping blindly. They felt their way up the walls, worming across the ceiling and the deck. One of them touched him. Its caress was like ice. The darkness closed in, drawing his robed body into its embrace.

A steaming breath touched his neck. It reeked of tainted nightmares and rotting flesh.

The creeping darkness whispered to him, a dozen voices of madness blended into one. Blood began to leak from his ears. The stylus in his hand began to twitch.

I will give you the means to overwhelm your mentor, if that is your wish.

'A precaution, only,' said Marduk. 'I feel there will come a time when it will be necessary.'

And in return?

The darkness was agitated, the shadows coiling around themselves and itching against the borders of reality.

'And in return I will find you a suitable host,' said Marduk.

Pledge it in the blood.

Marduk put down his stylus and drew his athame. Without hesitation he sliced it across the palm of his hand, blade biting deep. The shadows redoubled their agitated movement, crowding in close.

'This I pledge,' said Marduk, squeezing his hand into a fist and letting the blood flow. It hissed and smoked where it fell upon the carved Octed on the bench top. Then he took up his stylus once more, and allowed the daemon to guide his hand.

An hour passed. Perhaps more.

Hell retreated finally, uncoiling itself from him and sliding back through the worn-thin veil of reality. The brazier came back to life, flames crackling, and its low light filled the room once again. Marduk winced as he released his grip on the stylus. His hand was locked in a painful claw. In fact, his whole body ached.

He glanced down at the helmet still cradled in the arms of the calliper-stand: his mentor's helmet, now inscribed with a thousand upon a thousand curses. Not a single centimetre was untouched.

The handwriting was not his own.

All that the potent curse required was the speaking of a trigger phrase and his mentor would be undone.

'Let it be so,' he said.

Let it be so.

+ALL CHANNELS EMERGENCY BROADCAST PRIORITY CODE ALPHA-I TO ALL SHIPS WITHIN THE VERIDIAN SYSTEM++

+IDENT: Ultramarines battle-barge Constellation of Tarmus, tethered at high anchor over Calth++ +TRANSCRIPT FOLLOWS++.

This is Brother-Captain Ruben Indusio of the XIII Legion. We have suffered a catastrophic systems failure. Requesting immediate assistance. We have zero reactor capability, no weapons, no auspex. Please confirm, greenskin presence? We saw noth- Who's firing? Vox-master, open a link to the orbital. I need shields now, damn it.

[Detonation, followed by severe signal distortion]

Throne, the Sons of Ultramar! They're gone. We're trapped. Cut the docking lines, you damned fool! Cut them or we die here and now.

Brothers of the XVII Legion, cease fire! In the name of the Emperor, this is a mistake! You've made a mis- [Transmission terminated at Calth mark: -0.17.13]

+END TRANSCRIPT++.

It started during his second week below ground.

Jassiq Blanchot was on digging duty. He was nearing the end of his shift. The ache in his limbs from hauling collapsed rock was so constant, so enveloping, that his arms and legs didn't seem to belong to him anymore. For six hours, his work detail had chipped at the cave-in, dragging away hundreds of kilos of stone. The large chamber to the rear was filling up with debris, but the collapse was intractable. He could easily believe that the barrier went on forever. Still, he kept working. He loaded up a makeshift sled just a plasteel door and rope and began dragging it away from the dig. The rope worked deeper grooves into his neck and shoulders.

He leaned forward into his burden. As he was reaching the storage chamber, he crossed paths with Narya Mellisen. The lieutenant from the Numinus 61st Infantry was taking her empty sled back for another load.

'You lead a charmed life,' she said.

He stopped, brought up short. He'd just been thinking dark thoughts about eternity.

He was trapped in an underground arcology along with hundreds of other refugees. Over half the system had collapsed, hammered by the earth-shaking blows of the war on the surface, except 'war' was really too weak a word. 'Cataclysm' was closer to the truth. Could a simple war turn the universe upside down, and shatter his every taken-for-granted conception of how reality worked? He didn't think so. That was what cataclysms did.

So there was the little matter of soul-deep trauma added to the overcrowding, the shortage of basic supplies, the isolation from the rest of Calth's subterranean network, and the absence of any communication from the outside world since the warning voxed by Captain Ventanus of the Ultramarines. The surface of Calth was now being scoured by its agonised sun. Survival meant staying underground indefinitely underground was where the war now raged but it also meant escaping this particular arcology by somehow digging through who-knew-how-many thousands of metres of blocked tunnel. Blanchot was becoming quite comfortable with cataclysm.

A charmed life? Was Mellisen trying to be funny?

She didn't strike him as the joking sort. Her face was streaked with sweat and grime. A long burn from glancing las-fire ran from right cheek to temple. Her eyes, a pale green, were serious. They were not laughing. They didn't seem hopeless, though, either.

'I'm not sure what you mean,' Blanchot said. He ran a ragged sleeve over his brow. The cloth came away soaked.

'I heard that you were on Veridius Maxim.'

Yes, he had been there. He had been there to see the Word Bearers cruisers Annunciation and Gospel of Steel, and the heavier Vox Finalis move up to bracket the fort. They unleashed an interlacing web of lance and destructor-cannon fire so dense, so cont-inuous, that it was as if the star fort were caught in the birth of a star. Retaliatory fire was a brief, pointless flare of impotent anger. Death had come quickly to the fort, the implosion of its core unleashing, in turn, a nova outburst of agony, searing the void with a terminal cry. Precious few shuttles and salvation pods were launched before the end. Many of them were vaporised by the fort's destruction. XVII Legion fighters descended upon the others, predators striking at weak prey.

Blanchot's shuttle made it through. His impression of the flight from the star fort was a smear of end-times fragments. He had no memory of conscious, rational thought from the moment of the attack to the terrible arrival on the surface of Calth. What he retained, instead, were jagged shards of sense impressions. The bone-rattling shaking of the craft, which tested the limits of the g-force webbing's strength. The shriek of threat klaxons. The light and flame of the terrible revelation that so modestly called itself 'war.'

The hunters had caught up with the shuttle in the upper atmosphere. Blanchot had one clear memory of that event. He saw, through a viewing block, the shuttle's port wing sheared off by cannon shells. For a moment, the craft continued its controlled descent. Then it tumbled into a crazy, cartwheeling spin. The terror of that plunge was so absolute that it flooded all of his senses with white noise. There were no concrete images he could grasp until after the impact.

He had become self-aware again when he was standing on a rocky plain a dozen metres from the smouldering wreckage of the shuttle. He was surrounded by blackened, twisted remains some from the craft, many from his fellow passengers. He was the only survivor.

He did not know how he had emerged from the crash. He'd been thrown clear, he supposed, by the providence of blind luck. Thrown clear into a world of newborn bedlam. Before him was a storm of black smoke, fire and a monster's skeleton as big as a mountain range. It was a sight so colossal, so hideous in its contortions of ruin, that it defied comprehension. It was simply destruction, the concept given form, and it made him scream. It would not be until much later that he would learn that he had been looking at the infernal grave of Kalkas Fortalice.

He had stumbled away, then, through a shattered landscape, beneath a flaming sky. There had been no purpose to his steps, no direction, and no hope. He had moved through vistas of devastation that he revisited now every time he closed his eyes. He doubted that he would every truly escape them. Somehow, the luck that had deemed he should witness nightmare after nightmare, had guided him to this arcology in the last moments before the solar rage had reached Calth.

So yes, he had been on Veridius Maxim.

'That's right,' he said, simply.

'And you're alive.'

With that simple statement, she brought home the immensity of his good fortune. He felt ashamed of his despair. He had experienced horrors, but survived them all. He was, to his knowledge, the one remaining soul who could bear witness to the star fort's tragedy. His continued existence was so improbable; it could be nothing less than a miracle. He should be grateful.

With a swelling heart, he realised that he was.

The joy surprised him into a response more frank than cautious. 'I don't know if "charmed" is the right word,' he said, then caught himself, hoping he had sounded casual, nervous that he had not. He glanced around, but they were alone. The rest of the detail was at the barrier, thirty metres away. No one other than Mellisen would have heard him over the din of improvised digging tools.

The lieutenant's gaze was serious, unwavering. 'Blessed, then?' she asked, reading him easily and reassuring him at the same time.

So she, too, followed the Lectitio Divinitatus. He nodded. 'Blessed,' he agreed. The missing time wasn't inexplicable at all if he viewed his survival as miraculous.

Mellisen nodded. 'Then if you were spared, you are here for a reason,' she said. 'Why would you be saved only to die a slow, futile death here?'

'There would be no point in that.'

'Exactly. You have a destiny that must exist beyond this blocked tunnel. And if you do, then I must believe that so do the rest of us. Your presence here gives us hope.'

'Us?'

'Those with eyes to see,' she said, and smiled. When she did, the battle-scarred soldier vanished, replaced by a worshipful recipient of the God-Emperor's light. 'We aren't alone.' She clapped him on the shoulder. 'And we are getting out.'

'Yes,' he said to her as she moved away, 'we are.'

He started pulling his sled again, and it felt lighter. It was then, as he saw the first glimpse of a bright, possible future since the war had begun, that / dark and ready / it happened.

He blinked away the passing splinter of a thought, but then / a voice of razors, needles on bone / he heard the whisper. He stopped moving. Perhaps it had been an echo of the sled's grind against the stone floor. Perhaps his imagination.

He had thought whisper, but that was wrong, surely. No whisper sounded like that. Still, he looked around the space of the chamber. The cold light of guttering lumen orbs played over the heaps of broken rock. There was no one here. A doorway on the other side of the chamber opened onto another tunnel leading back to the main body of what remained of the arcology.

The scream came next. It was a howl of despair, of anger, of frustration, and of unending agony. Insects crawled down Blanchot's spine. His flesh puckered at a sudden cold. He held his breath, straining to hear past the deafening beat of his own heart, yet desperate to hear nothing at all.

His prayer was answered. The scream was not repeated.

After a minute, his heart stopped trying to batter its way out of his chest. Idiot, he thought. Alarmed by a scream. In this place of suffering, it tended to be more alarming when the screams stopped.

He'd been frightened by the acoustic travels of the pain of his fellow refugees. His cowardice shamed him.

So did his lack of feeling.

He decided to do penance by spending an hour after his shift helping Tal Verlun in the medicae centre. The designation was a label of necessity, not reality. The arcology was one of the oldest on Calth, and one of the smallest though there had been extensive under-surface construction, large portions of the complex had made use of the pre-existing honeycomb of natural caverns. And though living quarters and support facilities had also been constructed, this particular arcology was not primarily a hab. It was an archive, a repository of the bureaucratic, administrative and technological minutiae that had poured out of Kalkas Fortalice and Numinus City, as inevitable a by-product of those centres' existence as smoke from a fire. Records had to be kept, history had to be preserved, but preferably not piling up in the way of the production of more records and more history.

So the unwanted, yet precious, information was sent to this city-sized vault, where a skeleton staff of adepts managed the flow of arrivals and occasionally made abortive attempts to catalogue the infinite for the day when someone, anyone, would come, needing a very specific taxation entry from a decade ago. Blanchot had heard tales, in recent years, of a naive curator who had not only convinced himself that stored here was a goldmine of future exhibits for the Holophusikon, but had mounted a campaign as wrong-headed as it was obsessive to make his dream a reality.

That dream was ash and dust now. Ash from fires that had broken out across the arcology as the battles in Numinus City had brutalised the surface, and what lay below. Dust that would gather on records sealed off from human eyes forever.

The archive had never been designed as a shelter, and it did not have the strength to stand up to the tremors created by gods at war. Almost all of the newer zones had been destroyed, levels pancaking one on top of the other, annihilating everything that had been designed for habitation, including the original medicae facility. What remained were the caves and some of the tunnels that had been built to rationalise the warren of chambers. A few storage warehouses had survived, and there was food that might have seen a dozen people through the crisis. But not hundreds. There was an underground stream that flowed through one of the outlying caves. There was plenty of water, then, to ensure slow death by starvation. There were no beds, and the mountainous stacks of records took up so much space that there was barely room to stretch out and die.

The new medicae centre was a small cave just off the largest chamber. As a location, it worked: close to the greatest number of refugees, while allowing Verlun to create some measure of order as he tended the wounded, the sick and the dying. As an actual surgery, the space made very little sense. Iron boxes of records were stacked up along the walls, creating some room in the centre of the floor, where tables had been set up for the patients. All Verlun had for equipment was what he had carried in his pack, and that pack was the surgeon's last connection to his regiment. His uniform was gone, as were the men who had been under his charge. Blanchot knew, from fragments of conversation between Mellisen and Verlun, that the surgeon wasn't from the 61st. Beyond that, he didn't know what the man had gone through before arriving here. His eyes held the recent past contained behind iron doors. Blanchot respected the need to keep it there.

Blanchot made his way through the main chamber towards Verlun's domain. The records here had been removed altogether and burned, history erased to create a bit more space for the witnesses of Calth's agony. The shelving that had filled the chamber had been torn apart to create benches and other ramshackle sticks of furniture. Blanchot had to pick his way over sprawled limbs with every step. People slept where they fell, exhausted. The lucky ones found a wall to lean against, and the very fortunate had corners in which to curl up, as if becoming a ball would protect them from the misery of the universe for just a little while longer. The stench was a clammy mix of unwashed bodies and the gathering filth of collective living on the sword-edge of desperation. The floor was sticky with blood lying over other patches now dry and darkened. Time had passed since the onset of war, yet there seemed to be no end to the parade of wounds inflicted on that first, awful day. That end must come, Blanchot knew. The injured would heal, or they would die, and that parade would be finished.

But disease disease lurked in the shadows, and it marched closer with every day the refugees spent sealed in the arcology. The smell in this cave was its herald.

The closer Blanchot came to the medicae centre, the more ruined were the people he passed. To the right of the entrance were those who had seen Verlun. To the left were those who waited. The only difference between many of them was the presence of bandages. The medic's supply of drugs had been exhausted a few hours into the first day, so the most he could do was bind wounds.

The chorus of groans greeted Blanchot as he approached. This was what he had heard earlier. Of course it was. It was the constant music of the refuge.

On his left, Blanchot saw a family group: a middle-aged couple and an old woman. The man's shirt was soaked in blood, and the woman his wife, Blanchot guessed was cradling his head. His breathing was very shallow. The older woman sat behind them, propped up on one of the shelving benches, slumped against the cavern wall. Her eyes were open, favouring Blanchot with the unblinking, empty stare of the dead.

He thought of saying something to the other woman, but then the screams came again, no louder than before, still in the distance, and clearly not in this chamber. He looked around. No one else reacted. Either the people here were too deep in their own pain to notice, or they hadn't heard. Blanchot swallowed, throat very dry, and hurried into the medicae centre.

There was an infantry trooper on the table. His right leg was shredded below the knee, bone fragments sticking out like ivory hooks. Verlun was trying to hold him still with the help of his volunteer assistant, Krudge. The trooper's breathing and his cries were one and the same, an agonised, frantic, high-pitched wheeze. He thrashed, tugging his shattered leg out of Krudge's grip. Blanchot stepped forward to hold the man's thigh down while Krudge immobilised the patient.

Verlun nodded and picked up a chainsword. 'I'm sorry,' he said to the soldier. 'It has to be done, and at least it will be quick.'

'Please...' the soldier began, but Verlun drowned him out with the growl of the weapon.

The amputation was quick but messy / whispered hisssssss of satisfaction / and Blanchot almost retched. He kept his grip and stared hard at Krudge. The other man appeared to have his attention focused on his task. Blanchot kept watching him while Verlun worked to staunch the now unconscious trooper's bleeding.

'Will he live?' Krudge asked.

Verlun shrugged, exhausted. 'Long enough to have made this worthwhile? I don't know. Maybe.' The medic was a veteran, grey of hair, now grey of face, too. His shoulders were stooped, as if bearing the weight of the entire refugee population. 'Citizen Krudge,' he said, 'you've been here eight hours. Go get some rest. Adept Blanchot can help me now.'

'What about you?' Krudge grunted.

Verlun straightened up and gave his head a shake to throw off the fatigue. It seemed to work, as if declaring himself refreshed made it so. 'I'm fine for a bit longer, thank you.'

Krudge nodded to them both and limped out of the chamber. Blanchot wasn't sorry to see him go. The man disturbed him. Krudge looked old. Whether he was as ancient as he seemed, or simply aged by manufactorum labour, Blanchot didn't know. His face was cracked and weathered, like leather hide that was falling apart. At some point in the past, he had lost his left eye. The socket was covered over with a rusting metal plate. Scar tissue crept from beneath it all the way down to his cheek. His hair was long, sparse and fine, and the grey of oil-stained rockcrete. His mouth was an ugly, lopsided slash that dropped open on the right side. His legs were different lengths. So were his arms, though they were both long. His mere presence put Blanchot on edge. Even so, Blanchot didn't think it was Krudge who had snake-whispered to him as the blade had bitten down.

'Who's next?' Verlun asked, snapping him back to the moment.

'Uh...' he cleared his throat. 'There's a man with a chest wound. I think he's still alive, but there's a lot of blood.'

'No,' Verlun said. 'Pointless.'