Each boarding torpedo carried twenty Imperial Fists of the Legiones Astartes: genetically enhanced warriors clad in powered armour who knew no fear or pity. Their enemy bore marks of loyalty to Horus, the Emperor’s son who had turned on his father and thrust the Imperium into civil war. Red eyes with slit pupils, snarling beast heads and jagged eight pointed stars covered the hull of the ship and the flesh of its crew. The air had a greasy quality, a meat stink that penetrated the Imperial Fists’ sealed armour as they shot and hacked deeper into the ship. Blood dripped from their amber-yellow armour and tatters of flesh hung from their chainblades. There were thousands of crew on the ship: dreg ratings, servitors, command crew, technicians and armsmen. There were only a hundred Imperial Fists facing them but there would be no survivors.

Twenty-two minutes after boarding the ship the Imperial Fists found the sealed doors. They were over three times the height of a man and as wide as a battle tank. They did not know what was inside but that did not matter. Anything kept so safe must have been of great value to the enemy. Four melta charges later, a glowing hole had been bored through two metres of metal. The breach still glowing cherry red the first Imperial Fist moved through, bolt pistol raised, tracking for targets.

The space beyond was a bare chamber, tall and wide enough to take half a dozen Land Raiders side by side. The air was still, untouched by the rank haze that filled the rest of the ship, as if it had been kept separate and isolated. There were no jagged stars scratched into the metal of the floor, no red eyes set into the walls. At first it seemed empty, and then they saw the figure at the centre of the room. They advanced, red target runes in their helmet displays pulsing over the hunched man in grey. He sat on the floor, the discarded remains of food and crumpled parchment scattered around him. Thick chains led from bolts in the deck to shackles around his thin ankles. On his lap was a pile of yellow parchment. His hand held a crude quill made from a spar of metal; its tip was black.

The sergeant of the Imperial Fist boarding squad walked to within a blade swing of the man. More warriors spread out into the echoing chamber, weapons pointing in at him.

‘Who are you?’ asked the sergeant, his voice growling from his helmet’s speaker grille.

‘I am the last remembrancer,’ said the man.

THE NAMELESS FORTRESS hid from the sun on the dark side of Titan, as if turning its face from the light. A kilometre-wide disk of stone and armour, it hung in the void above the yellow moon. Reflected light from the bloated sphere of Saturn caught in the tops of its weapon towers, spilling jagged shadows across its surface. It had been a defence station, part of the network that protected the approaches to Terra. Now the treachery of Horus had given it a new purpose. Here in isolated cells suspected traitors and turncoats were kept and bled of their secrets. Thousands of gaolers kept its inmates alive until they were of no further use: until the questioners were finished with them. There were countless questions that demanded an answer and its cells were never empty.

Rogal Dorn would be the first primarch to set foot in the nameless fortress. It was not an honour he relished.

‘Vile,’ said Dorn, watching as the void fortress grew nearer on a viewscreen. He sat on a metal flight bench, the knuckles of his armoured gauntlet beneath his chin. The inside compartment of the Stormbird attack craft was dark, the light from the viewscreen casting the primarch’s face in corpse-cold light. Dark eyes set above sharp cheekbones, a nose that cut down in line with the slope of the forehead, a down-turned mouth framed by a strong jaw. It was a face of perfection set in anger and carved from stone.

‘It is unpleasant, but it is necessary, my lord,’ said a voice from the darkness behind Dorn. It was a low, deep voice, weighted with age. The primarch did not turn to look at the person who spoke, a grey presence standing on the edge of the light. There were just the two of them alone in the crew compartment. Rogal Dorn commanded the defence of Terra and millions of troops but came to this place with only one companion.

‘ Necessary, I have heard that often recently,’ growled Dorn, not looking away from the waiting fortress.

Behind Dorn the shadowed figure shifted forwards. Cold electric light fell across a face crossed by lines of age and scars of time. Like the primarch, the figure wore armour, light catching its edges but hiding its colours in shadow.

‘The enemy is inside us, lord. It does not only march against us on the battlefield, it walks amongst us,’ said the old warrior.

‘Trust is to be feared in this war then, captain?’ asked Dorn, his voice like the growl of distant thunder.

‘I speak the truth as I see it,’ said the old warrior.

‘Tell me, if it had not been my Imperial Fists that found him would I have known that Solomon Voss had been brought here?’ He turned away from the screen and looked at the old warrior with eyes that had vanished into pits of shadow. ‘What would have happened to him?’

The flickering blue light of the viewscreen spilled over the old warrior. Grey armour, without mark or rank, the hilt of a double handed sword visible from where it projected above his shoulders. The light glittered across the ghost of a sigil on the grey of his shoulder guard.

‘The same as must happen now: the truth must be found and after that whatever the truth demands must be done,’ said the old warrior. He could feel the primarch’s emotions radiating out from him, the violence chained behind a facade of stone.

‘I have seen my brothers burn worlds we created together, sent my sons against my brothers’ sons. I have unmade the heart of my father’s empire and clad it in iron. You think I wish to avoid the realities that face us?’

The old warrior waited a heartbeat before replying. ‘Yet you come here, my lord. You come to see a man who, in all likelihood, has been corrupted by Horus and the powers that cradle him.’ Rogal Dorn did not move but the old warrior could feel the danger in that stillness like a lion poised for the kill.

‘Have a care,’ said Dorn, in a whisper like a sword sliding from a scabbard.

‘Trust is a weakness in our armour, lord,’ said the warrior, looking directly at the primarch. Dorn stepped forwards, his eyes deliberately tracing the bare grey surfaces of armour that should have displayed Legion heraldry.

‘A strange sentiment from you, Iacton Qruze,’ said Dorn.

The old warrior nodded slowly, remembering the ideals and broken oaths that had brought him to this point in time. He had once been a captain in the Luna Wolves Legion, the Legion of Horus. He was almost the last of his kind, and he had nothing left but his oath to serve the Emperor, and the Emperor alone.

‘I have seen the price of blind trust, my lord. Trust must be proved.’

‘And because of that we must throw the ideals of the Imperium to the flames?’ said Dorn, leaning close to Qruze. Such focus from a primarch would have forced most mortals to their knees. Qruze held Dorn’s gaze without faltering. He knew his role in this. He had made an oath of moment that he would stand watch over Rogal Dorn’s judgement. His duty was to balance that judgement with questions.

‘You have intervened, and so the judgement on this man is yours. He lives at your word,’ said Qruze.

‘What if he is innocent?’ snapped Dorn. Qruze gave a weary smile.

‘That proves nothing, my lord. If he is a threat he must be destroyed.’

‘Is that what you are here to do?’ said Dorn, nodding at the hilt of the sword on Qruze’s back. ‘To play judge, jury and executioner?’

‘I am here to help you in your judgement. I do this for the Sigillite. This is his domain and I am his hand in this.’