Hindsight was a treacherous boon. All too often, what might have been was tantalising and worthless in equal measure. A hundred questions raced through Kaurtal's mind in that moment questions of blood and pain and the body-horror of sharing your flesh with an alien entity.

And Argel Tal would have replied with honesty, for he was no deceiver. He would have spoken of the changes, the wrenching of bone, the boiling of blood, and the madness of two voices sharing space inside one mind.

But Kaurtal asked none of these things. His racing heart refused anything but the fierce rush of temptation. 'And my choice?'

Argel Tal nodded, knowing in that moment just how this would end.

'You can starve yourself of all nourishment and carve holy symbols across your flesh,' he told Kaurtal, 'purifying your mortal form for the union to come. You may then return to me if you hear the calling of the Neverborn from behind the veil. If you survive the ritual, then I will offer you a taste of my blood to begin the communion, and lead you into a new life as one of the Gal Vorbak. The Neverborn will never refuse such a devoted host.'

Starvation. Purification. Trances and visions and scarification.

He did not fear the trials, for he knew no fear. Even so, he hesitated at the mutilation of his flesh. What if he failed the offering? What if he could not fully recover? What if he required extensive bionics even to stand and fight with his brothers in the future?

'You mentioned a choice,' Kaurtal prompted again.

'I did. You may undergo the necessary purifications as I've just explained. Or you can risk a cruder, more abrupt offering, and pray the Neverborn deem you worthy for union. That is how the first of us accepted this gift, though we didn't realise what was being offered at the time.'

'What if I choose the quicker path?' Kaurtal asked.

'It is much more dangerous. More likely to succeed, but failure brings death.'

'But if I choose it?'

Argel Tal gathered the right words. 'It was different for each of us. Some saw nothing but blackness, others saw our pasts, and others, such as Xaphen...' Argel Tal gestured to another statue being lifted onto a plinth. 'Xaphen saw the future. He saw what might come to pass, if the future unrolled along one of its many thousand possible pathways.'

Kaurtal needed no time to prepare an answer. 'I will walk the same path you walked, my lord.'

His eagerness did not make Argel Tal smile. Again, with hindsight, that would have meant something.

'Then once we are in the warp, I will take you to a specially unprotected part of the ship, away from the tenebrous guardianship of the Geller field. You will offer what I offered, and do as I did.'

'What should I offer? What must I do?'

Argel Tal drew a golden sword, clearly of Terran make, forged for the fists of the Legiones Custodes. It should not have flared into life in his hands, and yet the blade did just that. Little lightning-snakes rippled down the stolen steel.

'You must offer your life, Jerudai.' He rested the tip of the blade against his brother's throat. 'You must die.'

He started at the corpse's voice, but Jyrvash stood unmoving, unliving, slouched against the wall and pinned by the spears lancing through his body. The alkaline wind rattled against the dead man's armour, with little skitterings of blown grit.

'Jyrvash,' Kaurtal said. He knew no fear. There was no unease in his voice. No, none. None at all. A daemon living in your blood could not change that about you. Surely.

He ran his ridged bone spurs in a threatening, scraping caress down the skull's side.

'Jyrvash,' he said again.

Nothing. Just another ghost of Calth. Jyrvash's skinless head tilted and toppled, smashing on the rockcrete ground.

If it was an omen, Kaurtal could not imagine what it was supposed to portend. Things could hardly get much worse for the Word Bearers on this accursed world. Never before had overwhelming, lightning victory and drawn-out, grinding defeat colluded so closely.

Power armour thrummed louder nearby. A shadow danced at the edge of his vision. He turned again, feeling his fingers harden, lengthen, the skin retracting around curved claws. Where a human's reaction to unease was seen in an elevated heart rate and the onset of fear-sweat, Kaurtal's body reacted by forging weapons from his flesh, shifting him into the divine murderousness of his killing form. Bones creaked and stretched. Flesh ripped and reformed. It was not agony, but nor was it painless.

He stared down the deserted avenue, his senses bladed and beast-keen. The bodies lay as they had lain before, and the buildings still stood as silent as kilometre-high tombstones driven into the dirt.

Kaurtal, came the voice from inside. The suddenness of it peeled the lips back from his teeth, and for the first time in months, he felt a stirring from the daemon within. A sluggish sensation, like something turgid in the silt at the bottom of a lake. His blood thickened with it, and the bony protrusions spiking out from his armour gave sympathetic aches. He could feel the presence within questing with its senses, stretching out tendrils of consciousness and withdrawing them in a lazy re-coiling.

We are no longer within the caverns? It was not exactly speech. The daemon's thoughts coalesced in Kaurtal's skull only slightly more slowly than his own inner monologue. A 'conversation' with the creature inside was as simple and subtle as the seamless transference of ideas and concepts at the merest whim.

You have slumbered, Kaurtal pulsed back, for over three months. This is the surface.

My wounds forced the silence of slumber. Was there the blade's edge of defensiveness in the daemon's thoughts? Kaurtal was quite sure there was. The blue warp-weaver is dead?

He recalled the battle. Some agonies wormed their way into the mind, as unshakeable as a splinter beneath a nail, and witch-lightning tearing at your very soul was one of them. The pain had been... revelatory. He dimly remembered laughing, learning, even as merciful grey mist threatened to drown his consciousness. Even as his blood boiled in his veins, and his second soul had fallen into untouchable darkness.

The Librarian is dead, Kaurtal sent back. Three months in his grave, dead by my hand. I have left the Underworld War behind.

I hunger.

There is no blood on the surface.

The daemon stretched itself through Kaurtal's body, filling his bones all the way to his toes and fingertips. Muscle twitches made his fingers flicker, and his left eyelid started to spasm.

But I hunger, the daemon said again. Kaurtal's teeth clacked together as sentient pain oozed through the bones of his jaw.

'I hunger,' the daemon said again, this time with the Word Bearer's mouth.

Kaurtal repressed a shudder, then repressed the symbiote itself. It took focus, but concentration shackled the daemon from making any claim over his physical form. Calculus equations always worked best for Kaurtal. Some of the Gal Vorbak prayed, or simply gave in to their skin-riding daemons, letting the Neverborn claim them at will, but Kaurtal had always suppressed his sacred parasite with the repetition of long, involved calculations. Reciting and solving them occupied his mind, keeping his thoughts free of the creature's passions.

Our wings hurt, Jerudai.

They atrophied. We were in the dark too long.

I hunger.

Enough. We have a duty up here.

The daemon slithered through his veins. He felt it coiling tight around his spine, just as he felt it licking at the filament nerves behind his eyeballs.

What duty?

Kaurtal turned from the headless corpse of his fallen brother, moving away through the urban detritus.

A duty to make the Legion remember us. I am gathering relics from each Chapter that d The daemon's displeasure came as a jolt of pain in the looping cables of Kaurtal's bowels.

Legions and pride and memories and brotherhood. Man-concerns. Man-duties. Let us hunt and feed and No. His interruption was as smooth as the daemon's had been, and just as forceful. Kaurtal's mouth was a mangled mess of ceramite and ivory teeth. He spat blood onto the road. No. This matters to me.

Slits gashed open in the side of his arm. Four new eyes, each one yellowishly reptilian, opened and regarded the dead city. They rolled in their ceramite-and-muscle sockets, then closed and sealed over. Kaurtal felt others opening on his shoulder blades, and another by his knee. These also rolled and stared, before sealing closed in viscous, moist whispers.

Something moved under his ribcage. Something else moved in his guts. He sensed the daemon's disgust.

You are hollowed through by cancers. They hang inside you, these black fruits, staining your body with sickness. You would die without me, Jerudai. This pilgrimage on the surface will see you dead.

The sun is still poison, he sent back.

I can see that better than you, host. The daemon did something inside his chest. There was the grainy, fluid feeling of thick juice flowing across his insides. I can pulp these black fruits, rip them from their cradles of flesh and bone, and dissolve them into your bloodstream. There will be pain.

There's always pain.

Silence now. Let me save us from the foolishness of Man-pride.

Kaurtal took three steps before his swimming vision drove him to his knees. His Legion-granted sensory organs had compensated for any dizziness since their implantation back in his dimly-recalled childhood, so disorientation was as unfamiliar as it was unwelcome. Yet he thudded down onto his hands and knees, dizzy as a drunkard, while something serpentine slipped behind his eyes and started gnawing on the meat of his mind.

Your brain is ripe with corruption. It is a wonder you aren't blind.

Kaurtal felt his fangs clench together, cutting the street's silence with a porcelain squeal. One of his claws broke against the rockcrete, but the aborted talon lengthened fresh from the bleeding finger once more.

To his left, half a metre from his clawed hand, a dead Word Bearer regarded him with eye lenses the colour of fresh frost.

'Brother,' he greeted the corpse, feeling the sick urge to laugh. Its armour was too bolter-blasted to offer any hint of identity. All that mattered were the god-runes carved into its ceramite. That much at least, Kaurtal would remember and bring back to the Legion. He had Jyrvash's knife as evidence.

The dead warrior regarded him with its ice-pale eye lenses.

'Kaurtal,' it said. Its voice was the alkaline wind itself, formed of whispers and the clatter of dust against armour. 'You have abandoned us.'

He had chosen the quicker path, as he suspected every Word Bearer offered this rare gift would surely choose themselves. What manner of faithless coward would hesitate in the face of a chance to bond with the Divine? He wished to be blessed as the Gal Vorbak were blessed, not spend months in sedate prayer.

'Do it,' he had said to Argel Tal. He had even leaned his head back, baring his throat.

But the Crimson Lord sheathed his blade, and returned his gaze to the statues being lifted into place.

'Tomorrow,' the other warrior said in his curious dual-voice. 'Go back to your ship, Jerudai. Reflect on what I offer, and if you wish to die tomorrow, then I will kill you myself.'

He had done as he was bidden. While aboard the Mournsong, flagship of the Twisting Rune Chapter, he had avoided his squad and refused to take counsel with any of his brothers. The Chaplain came to him, requesting entry into his meditation chambers, but Kaurtal sent the warrior-priest away with a plea for solitude.

The next night, he secured teleportation passage back to the Fidelitas Lex. As dangerous as such translocation was while both ships were at the mercy of the warp's tides, taking an unshielded gunship would be an act of suicidal futility.

When the shrieking, snaking mist of teleportation cleared, Argel Tal was already waiting for him. Robed thralls chanted and prayed, while servitors worked at the chamber's edges, murmuring as they adjusted the hand-wrenched, archaic clockwork machinery.

Argel Tal was helmed now. Kaurtal acknowledged his lord's presence with a salute, fist over his heart, though they seemed past such mundane forms of address.

'You knew I'd come,' he said.

Argel Tal's only answer was to draw his sword and walk away.

Kaurtal followed.

He scrambled to his feet, wings flaring wide, the looted bolter weighty in his fist. Its sculpted muzzle aimed down at the dead body, defying the corpse to move, to speak, to betray any one aspect of a life that it should not possess.

Nerkhulum, he said, voiceless and inwardly.

I said to be silent. Do you believe it is easy to re-weave mortal matter? Your flesh is weakened from the sun, and reshaping it is causing you to bleed within. Let me work on saving us, Jerudai.

The Word Bearer stood in the street, breathing heavily, both hearts beating hard.

You didn't hear that? he almost shouted.

I hear the liquid whispers of your straining, cancerous organs. I hear them as your reward for abandoning the Legion.

Something is alive here. He kept the bolter aimed down.

Nothing is alive here. The cancers riddling your skull put pressure on your brain and toy with your senses. Nothing more.

That sounded right. It sounded true.

And yet it felt like a lie.

He was stronger with the daemon awake. His senses were more keen, reaching out further. Nothing moved, not on the street, not in the hollow windows of the battered hab-spires. He could smell the charcoal corrosion of decaying tanks, and the cinnamon after-musk of long-rotted bodies. The smell of a slain city.

The dead were dead. They did not speak. They did not accuse you of deserting your brothers, and forsaking your duty.

Kaurtal fired, and annihilated the helmet in a burst of scattering shrapnel and bone shards.

Petty, came the daemon's voice. If it was not a spoken word, it was still the closest the Word Bearer's mind could come to giving shape to the daemon's bored chastisement.

For a moment, he stood in the road, looking down at the trinkets and relics bound to his armour. Mementos of fallen Chapters, left over after a bitter victory, now languishing outside of the XVII Legion's memory.

Someone had to do this. Someone had to make them remember the fallen. Eight years ago, he had stood in one of the flagship's cemeteries with Argel Tal himself, seeing dead warriors being enshrined in marble and bronze. The slain of Isstvan, remembered with honour for their sacrifice. What justice for the slain of Calth?

He would stand before Lorgar and cast the relics of lost Chapters down at his primarch's feet. Nothing else mattered.

Not long after Kaurtal left Jyrvash behind, he came across the body of a dead Titan. It was said that the Mechanicus priests fashioned their humanoid war engines to stand in the Machine God's image, as totemic as any theist avatar from before Old Night, but the Reaver was much less grand in its morbid repose. A dead machine lying in the dust, all sense of connection to its masters' species gone as it lay broken across the churned earth.

The kill-wound was not hard to see. Rocket-punctures pitted and cracked the Reaver's face like cratered acne. The command crew likely had not even suffered when the end came. A flash of flame, an immolated cockpit, and they would be dead before their Titan hit the ground.

Kaurtal landed upon its shoulder, clawed boots digging into the corroded plating. It made a good vantage point from which to look out over the destroyed plaza. Corrosion had eaten deep into the Titan's armour-plating, making it difficult to determine the Titan's original allegiance. Dead warriors from both Legions lay strewn around its fallen bulk, but a habitation spire had toppled in the avenue to the east, leaving a half-metre of dust and debris blanketing the ground and shrouding the dead with ash. Irregular mounds marked the final resting places of countless warriors. It was the closest thing to a real graveyard that the dead on Calth's surface would ever see.

Nerkhulum remained silent, presumably working to excise the poisoned meat from the Word Bearer's body.

Kaurtal dropped down, wading through the dirt and debris. His red armour turned grey to the waist as he kicked up the dust merely by walking. The first body he hauled from its powdery cairn was an Ultramarine, clad in rotted cobalt-blue, and he let it tumble back into the dry muck. Dust-devils swirled, protesting the irreverent way he disturbed the fallen.

The second was also an Ultramarine. As was the third.

He found a Word Bearer, but the corpse's arm cracked from its shoulder when he tried to lift the remains. Brushing aside more dust revealed the faded, greyed-red ceramite he had been seeking, along with the emblem across the breastplate: a face, pale against the dark background, shaped as a sorrowful masquerade mask. The Chapter of the Iron Veil.

Kaurtal reached down to grip the mask's edges, ready to pry the ivory emblem clear of the armour-plating. He thumped a boot onto the corpse for leverage, bunched his muscles, and pulled.

'Kaurtal,' the half-buried body choked, like a man gagging on ashes.

He released the chestplate, but the dead Word Bearer kept rising, dust sluicing from the old armour ceramite, hissing as it slid free. Kaurtal backed away, claws lengthening, acidic saliva stringing between his malformed teeth. He backed right into something cold and dusty, and just as dead.