The Terminator trudged through the deeper blackness, its heavy tread giving an echoing rumble. The only light was that which they brought with them: the iceburn blue-white glare of their eye lenses. Onwards they walked, into the silence, breaking the serenity with boot-steps on stone and grinding armour joints.

'Do we not deserve their reverence?' Thuul asked. He had the voice of a scholarly avalanche. 'And do the gods not deserve worship?'

As Kaurtal walked, he let his gloved hand trail across the jagged rock wall. 'The gods have abandoned us,' he said. 'As has Lorgar.'

Thuul's tusked helm gave a rattle of vox that sounded like a slipping gear wheel. 'Blasphemy, brother? From one of the exalted Gal Vorbak?'

Kaurtal's laughter was dry in the dark. 'It has been more than half a decade since Kor Phaeron fled. Seven years of these tunnels lit by ritual fires and the muzzle flash of enemy bolters. Seven years of smelling the salt-stink of human sweat, and the spicy musk of leaking sores growing from radiation burns. Lorgar is not coming back for us, Thuul. He was never coming back for us.'

'The sun still bleeds poison into the void.'

'Calth's surface may be lethal to life, but the ebb of a dying sun hardly threatens a rescue fleet, shielded against the radiation.'

Thuul rounded on him. 'Rescue is a coward's word, Jerudai.'

'Call it whatever you wish. Would our lordly father even need a fleet? He hears the warp's song. He weaves it and rends it with the ease of silk. Why not carve reality open and come to our aid?'

There was a pause as Thuul mused on this. 'You drank from the Blessed Son's wrist and tasted the divine blood. How can you, of all the Legion, bring this blasphemy to me? What madness incites you to walk this holy darkness and speak such heresy?'

'Speak the truth,' Kaurtal quoted without a smile, 'even if your voice shakes.'

The Terminator trudged on. Kaurtal allowed the silence for a time, but he was not the most patient soul ever to wear the red of the XVII.

'Have you noticed that after two years, even the empty tunnels smell of blood?'

Thuul grunted acknowledgement, but said nothing more.

'Your servants have been mauled,' Kaurtal prompted.

'Yesterday,' Thuul replied.

'The Thirteenth hit you hard.'

'Harder than you realise,' said Thuul. 'The blood you're smelling is mine.'

His war-plate was as ruined as Kaurtal's as ruined as every Word Bearer stranded on this dead world of cavern-cities. The scent of leaking life could be coming from any one of the charred ruptures in the thick plating. He tapped an armoured fist against his chestplate, breaking the silence with a steel-drum clang. 'One of my hearts has stopped beating. The other labours even now. I may have a few days remaining to me, but no more than a handful. The gods only know what's burst inside me.'

There was another long silence before Kaurtal spoke again.

'I have been moving through the underworld. Fighting when I must, but more often merely watching, waiting. Learning.'

Thuul regarded him with soulless eye lenses, awaiting an explanation. Kaurtal gave it with a sigh. 'I have been counting the dead. Taking heed of all that now lie lifeless.'

'Thousands of the Ultramarines have fallen,' the Terminator said. His voice was sincere enough to make the words an avowal. 'Perhaps tens of thousands.'

'I am not speaking about counting them, Thuul.'

Another pause. Kaurtal could almost hear Thuul's thoughts, whispering and clicking with displeasure.

'I'm going to the surface,' Kaurtal said at last.

Thuul turned his tusked helm to the other warrior. 'To go to the surface is to die.'

'For you, perhaps. I am Gal Vorbak. My blood is poison. My touch corrodes flesh. I have eaten nothing but ash for over a year.' He showed his gauntlet, the red ceramite ridged and knuckled with bleached skeletal spurs. The same growths showed across his war-plate his bones had been hardening and pushing through the ceramite as the months passed in the dark. Surprisingly, the pain had been nothing more than a dull throb, no different from the muscle aches of daily training.

The Terminator gave his passive regard. 'You believe the daemon inside you renders you immune to the radiation of a sickened sun?'

Not an easy question to answer. The daemon within him had been silent and unreachable for months. He was half-convinced that his last battle with an Ultramarines Librarian had somehow left him depleted perhaps exorcised was a truer word with the divinity flayed from his flesh. The Emperors lapdogs were beginning to realise the value of the forbidden Librarius once more.

'I believe we'll see soon enough.' Kaurtal's wings gave another shiver. Closed tight to his back, they were a worthless cloak of thick-veined, folded leathery membranes. He had not flown in months. Few caverns were spacious enough to allow such freedom.

'But why the surface, brother? What awaits you there?'

'The dead,' Kaurtal replied. 'I intend to live. I will escape Calth, even if I am the only Word Bearer to do so. And I will remember who died here. I will make the Legion remember.'

'They already remember. We cannot leave until the war is won.'

'You are deluding yourself.' Kaurtal lifted an arm, where a beaten-iron star medallion was bolted and hammered into the ceramite of his forearm. 'Where is the Graven Star?' He turned his hand, showing a ritual engraving of a sinuous serpent. 'Where are the Asps of the Sacred Sands?' He reached to his chestplate, where a ruined parchment showed the faint signs of a red palm print. 'Where is the Flayed Hand? I will tell you, Thuul. The Graven Star are dead. The Asps of the Sacred Sands are dead. The Flayed Hand are corpses at the bottom of a pit, skulls leering up in silent laughter at their fate, lost to an Ultramarines ambush. How many of us remain? We lead starving weaklings in a war with only one end the Thirteenth will destroy us, and our own Legion will remember none of it.'

Kaurtal turned his pauldron as he spoke, showing the mangled sigil of the Twisting Rune Chapter. 'How many Chapters have died down here, Thuul? It has been seven years. Where are your brothers?' He gestured to the snarling daemon face on the Terminator's shoulder guard. 'Where are the rest of Hol Beloth's men?'

The two Word Bearers stood in the pregnant silence, saying no more. To Kaurtal, the dark cavern was a manifestation of every other cave; it embodied every night spent down here in the lightless, blood-smelling black.

Thuul finally spoke. 'You truly mean to abandon the Legion, Jerudai?'

'They abandoned us,' Kaurtal replied. 'Lorgar isn't coming. The Legion has left us here to die. I am going to the surface.'

'You are damning yourself to apostasy.' The Terminator growled a Colchisian command, and blades lengthened from their housings on the back of his oversized gauntlets. 'And you know I must kill you for even voicing all this,' admitted Thuul.

Kaurtal nodded. 'I know you must try.'

Bad secrets always tended to be buried the deepest. After leaving Thuul's cavern, bloodstained and even more battered than when he had arrived, it took Kaurtal almost a month to reach the surface. The journey was not an easy one. The Underworld War raged, as it had raged for almost seven years, in brutal spits and spurts, filling the caves with the grind of overwhelming violence for several nights, then fading back to give a few hours of respite.

Kaurtal had fought on Isstvan V, when the skies burned black from the funeral pyres of three butchered Legions. Until he had been forced to burrow beneath the surface of Calth, he had honestly believed Isstvan to be the pinnacle of what was possible in war.

The apostate walked west once he abandoned his brothers below. Always west, towards the setting arc of the poisoned sun. Its swollen blue malignancy stained the sky: cancerous in imagery, and in the realities of its radiation.

He was sweating inside his armour, in the places where his armour had not yet become his skin. Where his flesh had fused with the ceramite, he either did not need to sweat, or simply had not encountered conditions vile enough to bring about a bodily reaction. Sometimes he coughed up blood, expelling it through the maw of bestial teeth his helm's mouth grille had become. That was not the radiation. That was just his body adapting.

The ghosts of Calth fought as he went west. They paid him no heed, for they were mere memory, and he was iron and blood and bone. The apostate Word Bearer heard their shouts and cries, seeing the dead warriors as flashes and flickers at the edge of his vision. He listened as they waged a war both sides had already lost, reprising their roles from the day this world had died.

When he did not walk, he flew. Before Calth, his wings had been beautiful things: a swan's pinions, white-feathered and clean. The Underworld War leeched their health, shedding feathers like autumn leaves, accelerating the Change as the daemon within exerted its influence over his genetic code. The swan's wings had become something bony and bladed, a spread of leathery flesh with thick veins in lightning-bolt patterns across the silken membranes. Stronger now, without a doubt. More useful.

Stronger, but stranger. They smelled of animal musk, and they sweated blood. Stretching them felt no different from holding one's arms wide.

Despite the weight of his armour, beating them three times was enough to lift him from the ground. He could not fly for long, though, for the effort sapped all strength from his muscles, but once high enough he could glide for an hour or more.

He did not sleep on his travels. He had evolved beyond the need for it, even beyond the slack limits of his regenesis among the Legiones Astartes. He no longer needed to eat, though thirst was ever a plague. Dehydration thickened his tongue. Swallowing his own saliva was a blessed but false relief. Sometimes, he would swallow his own blood.

He journeyed across the unending plains, crunching the blackened husk of vegetation beneath his boots. An ocean of unharvested crops, dried and rotted from the dragon-breath heat of an irradiated sun.

On the ninth day of his journey, he walked through a dirt storm. Solar radiation tortured Calth, toyed with it, making a mockery of its weather patterns. The apostate saw the horizon darken with the coming maelstrom a tidal wave of earth-dust and tormented soil. He prepared for it as it rolled down from the western mountains, though those preparations consisted of nothing more than folding his wings tighter to his back. Instinct made him reach to check the conductive strip of mag-locking metal that bound his bolter to his thigh... but he reached for thin air. He had lost his last gun long ago.

When the winds howled their highest, and grit clattered against his ceramite armour in a ceaseless, gravelly barrage, the apostate trudged on through the darkness, blinded by the dust of this violated world. He could all too easily imagine that the planet hated him as if the world's soul sensed the last defiler upon its surface and wheezed its last, dirty breaths to spite him. He knew war, and he knew how warriors died. How many slipped into death with a final curse on their lips? Calth itself, evidently, was no different.

He reached the first graveyard on the eleventh day. This was why he had come to the surface. This was why he was here. Someone had to remember.

The graveyard owed nothing to the stately order of rural cemeteries with their rows of stone tablets, and resembled even less the sand-blasted menhir henges of Colchisian burial grounds. Here was carnage, spread thick across the churned earth. Tank hulls rotted in the sickly light, darkened by rust, giving infected-teeth leers from their corroded dozer blades. The bodies were mummified in their sundered armour, cracked open to desiccate in the wounded glow of Veridia.

Kaurtal hiked through the slain, seeking the sigils carved and burned and sculpted onto shoulder guards. On every red-armoured corpse, the same grey-painted skull glared. Its mouth was an iron lock, closed to silence all speech.

The Unspeaking. The Unspeaking died here, annihilated beneath an Ultramarines counterattack.

These bodies were not from his Chapter, then. The Unspeaking were warrior-sages to match any others, stilling their tongues with proud, proud oaths of silence. Kaurtal respected them, but had little to do with their works.

Among the Word Bearers dead lay hundreds of ragged skeletons clad in shreds of cloth and dirty rags. The Unspeaking's faithful followers, no doubt. After nearly seven years in the tainted sun they were little more than husks, but he knew that if he had chanced upon this gravesite in the hours after the battle, opening their slack jaws would reveal tongueless maws a display of the Unspeaking's ritual mutilation for its oath-sworn serfs.

Kaurtal took two things from the unburied dead. The first was a bolter, graven with kill-markings and patchy with corrosion, but proven functional after a test shot sent a shell pounding into the armour-plating of a nearby Rhino. He felt no guilt at breaking the silence of this massacre site. He could not inflict any greater indignity upon them than that which they had already endured, baked to the bone by a fouled sun.

The second thing he stole was a talisman from around a warrior's neck. A simple necklace of cheap bronze with the warrior's name, squad designation and Chapter symbol scripted in Colchisian cuneiform. A rare token the habit was much more common among the lesser soldiers of the Imperial Army, with their identification tags necessary for collating casualties. As if anyone would care about the management of mere human corpses in a war led by the Legions.

He tied the trinket around his wrist and walked west, leaving the first graveyard behind.

He reached Dainhold three days later.

The city lay in dust a skyscape of toppled towers and dead spires, with streets torn raw in the wake of tank treads. The chasm-scars of orbital bombardment were graven deep across the city's fallen districts, where lance fire raked its way across the population centres and slaughtered the city before it even knew it was under attack.

He had fought here after making planetfall. He had fought his way through the burning city, throwing himself at Ultramarines shield-walls, or firing back from behind barricades of tumbled rock and ruined bodies. The running firefights had none of the claustrophobic choke so omnipresent and overplayed in the underworld. Bolters had fired that day without echoing against the confining stone.

How good it had been to fight freely. He had even flown, spreading his wings to soar above the embattled streets, firing at will on the helpless warriors below.

But that was then, and this was now.

Kaurtal ventured into the city, making his way down the silent roads, walking around shattered tanks and fallen buildings. Spires still rose in ruined grandeur, their sides blasted open to the light of the lethal sky. Bodies were skinless, sinewless bones, many fallen onto the rockcrete ground in reach of inactive lasguns and solid-shot rifles. Many more had died unarmed, huddled together or alone; some with their remains scattered across roads or plazas, others squatting in corners or ducking under cover. Perhaps instinct had sent them fleeing and scurrying in those last moments. Perhaps they had died when the sky rained fire, or when the Warmaster's allies brought Calth to heel with bolter and blade.

Mere minutes into the city, he found his first Word Bearers.

Kaurtal thudded to the ground, boots cracking the rockcrete as he hit, and bunched his wings to his back. The avenue was a scene from some visionary's sketch of a pre-Unity mythic hell, with Ultramarines and Word Bearers gone to the bone within their armour, spitted by spears and making barricades with their own bodies.

He walked amongst the dead, letting his fingers brush delicately over their broken ceramite. One Ultramarine was nothing more than powder and armour fragments beneath a Fellblade's treads a lone armoured arm reached out from beneath the dead tank as the only indication that a warrior had died under there. One of the Word Bearers was lanced thrice through the chest, pinned to the stone wall of a habitation spire. Four hundred dead warriors, and the bones of their war-thralls at their feet.

A low hum pervaded the scene, setting Kaurtal's teeth on edge. Some of the dead Space Marines' suits of armour were still active after all this time, still thrumming in tune with their back-mounted power packs.

It was one corpse in particular that most drew Kaurtal's eye. He approached it with a certain confident caution, the way a medium might prepare to make contact with the restless dead. The slain Word Bearer's armour was decorated with gold runes, god-sigils on arterial red, the markings of the Inscribed. Kaurtal knew the Chapter well.

'Hello, Jyrvash,' he said to the impaled captain.

Jyrvash did not reply. Jyrvash did not move at all.

Kaurtal reached up to his brother's helm, unlocking the seals at the dead warrior's collar. A serpent's hiss of vented air pressure allowed the helmet to come free, and he looked upon the dry-leather skull that had been Jyrvash's face. The smell of decomposition, freed at last, was a gaseous corruption intense enough to make Kaurtal's eyes sting. As a child on the streets of the City of Grey Flowers, he had seen bloodfly eggs burst open in the belly of a dead dog this smell was the same. He had evolved past disgust, but not past the bite of bitter memory.

'You died badly, Jyrvash.' His tone stole any possibility of the words being a question. 'But then, doesn't everyone...'

The skull stared back, its hollow eye sockets neither knowing nor agreeing; merely pits to display the absence of life and personality.

Kaurtal let the helm drop to the road, and reached for the ornate dagger sheathed at the dead warrior's hip. More god-runes marked the rusted blade. Another memento. Another Chapter to remember.

He turned away, stretching his wings and bunching his muscles to leap skyward.

'Kaurtal,' said the corpse behind him.

A year before Calth, in the days that followed Isstvan V, Kaurtal had been summoned to the Fidelitas Lex. He had anticipated delivering a report on the Twisting Rune's casualties from the killing fields, or perhaps a briefing regarding new recruitment to ease the savage losses that they had sustained fighting against the Raven Guard.

He had, of course, assumed wrong. He had actually been summoned to his death.

Argel Tal, the Crimson Lord, was already spoken of in whispers across the fleet. He and his men the so-called Blessed Sons had shown the truths of their divine forms. They were god-touched, no longer human or legionary, but a sacred bonding of flesh and spirit. Possessed, in the crudest terms; ascended, by any other judgement. The Crimson Lord waited in the funerary chambers aboard the Lex, watching servitors raise bronze and marble statues of those slain in the recent massacre.

Argel Tal wore the red ceramite not yet adopted by the rest of the Legion that would soon change, as they armoured themselves in arterial crimson before the betrayal at Calth. His face was the dusky tan of all desert-born Word Bearers, and his eyes showed a repression of emotion that danced somewhere between unshared pain and unreleased anger. He spoke softly, calmly, but it seemed an effort to do either.

'Sergeant,' Argel Tal said, by way of greeting. He spoke in two voices now: his own soft tones, and the bass rumble of the thing inside him.

Kaurtal was no longer sure of Argel Tal's rank since his Change, and said as much. That brought a tight, tense smile to the other warrior's lips.

'Gal Vorbak,' Argel Tal replied. 'For now.'

The Crimson Lord would soon create the Vakrah Jal the Chapter of Consecrated Iron but Kaurtal had had no idea of it back then. Even if he had, it still would not have aroused his suspicions. Not so soon after their victory on Isstvan.

Argel Tal said nothing more. He was watching the servitors raise a statue of a slender young woman in a flowing dress-robe.

'It's true, then,' Kaurtal ventured. 'The Blessed Lady has fallen.'

'Warriors fall,' Argel Tal turned to Kaurtal, his words punctuated by the slither of lengthening teeth. 'She was murdered.'

'An ill omen,' Kaurtal said quietly.

'I will not argue with that,' the other warrior replied. They settled into a companionable silence for several seconds, watching the servitors work.

'Why was I summoned?' Kaurtal asked him. 'Have I displeased Lord Aurelian?'

'Far from it. He wishes to offer you a gift.'

Something in the Gal Vorbak's tone made Kaurtal's skin crawl. He repeated the words with measured neutrality. 'A gift.'

'You have a choice.' The Crimson Lord was either deaf to his brother's trepidation, or chose to ignore it. 'Lorgar has bid me increase the numbers of the Gal Vorbak. He desires more Blessed Sons, among both the Calth assault force and the fleets tasked to spread across Ultramar.'

Kaurtal's breath caught in his throat. 'You can do this? Mesh flesh and spirit at will?'

'The primarch has asked, and I will obey.'