The phase field sprang into life, looking like a cone of pearlescent energy. Everything within the field disappeared, including a circle of the Tower Eight wall some three metres in diameter. After a few seconds, Midoa signalled for the machine to be shut down and with his squad on his heels, stepped through the newly-made gap.

Inside, the phase field had displaced a swathe of the room within the tower, along with another interior wall and the ceiling twenty metres further on, exposing the floor above and a basement level below. Neatly severed cables sparked while sliced atmosphere recycling pipes dribbled contaminant-laden steam into the air. Their suit lamps piercing the darkness inside the tower, the Iron Hands pushed on with weapons ready.

'What do you mean, Tower Eight has been breached?' Calas Typhon, First Captain of the Death Guard Legion, Commander of the Grave Wardens, was in a foul mood already, and the news of the Iron Hands' success did not improve his humour.

'A phase field generator, commander,' replied his second, Captain Vioss, who was forced to take a step back as his senior turned; Typhon and his subordinate's massive suits of Terminator armour almost filled the command blister on the top of Tower Seven. Vioss's voice was a low, slurred hiss, his speech impaired by an ugly suppurating wound in the right side of his jaw. 'Sarrin had too much focus on the gateways and the breach through the wall has him outflanked.'

'Why now?' demanded Typhon, his top-knot of dark hair flicking like a horse's tail as he twitched his head in annoyance. 'Have they received some signal from the Dark Angels?'

'Impossible, commander,' said Vioss. 'The Terminus Est's dearthfield is still functioning, no communication is able to pass from surface to outer orbit.'

'And the Dark Angels continue on their course directly towards Perditus Ultima?'

Vioss nodded, his sallow face deeply creased by a scowl.

'They will have orbit in less than two hours, commander.'

'Then we have less than two hours to punish our idiot foe for his foolhardiness. He should have waited until orbital supremacy was guaranteed. Signal the fleet and tell them to stave off engagement as long as possible. That should afford us an extra hour at least while the Dark Angels are forced to consider their options.'

'You plan to bring forward the next attack, commander?'

'Yes, right now, may the Father take your eyes!' Typhon crashed his fist into Vioss's shoulder, sending him reeling into the wall of the glassite-domed cupola. Motes of rust drifted in the air from the impact, shed from the corroded edges of Vioss's armour. 'We must free Tuchulcha while we have the chance. A lot depends on our success here. Tell Ghrusul to assault from Tower Nine, we will trap our enemy between us and drive onwards to the central facility.'

'For the Father,' said Vioss, bowing his head. 'The Grave Wardens will not fail.'

The subterranean passageway was five metres high and twice as broad, lit by thin, dust-covered yellow strips in the floor and ceiling. The rails of an ancient locomotive system rusted at the centre of the tunnel and raised platforms ran along the walls to either side. Normally it was a gloomy place, but the arrival of the Iron Hands and Death Guard had turned it into a place of pyrotechnic brilliance.

Bolter fire echoed along the five-hundred-metre length of the interchange, the shells expelled by the exchange hurtling in both directions in a criss-cross of bright flares. Now and then the miniature blue star of a plasma shot shrieked across the gap or the red flare of a missile trail illuminated the murkiness. Blossoms of frag missile detonations appeared amongst the line of twenty Death Guard Terminators advancing on Tower Eight.

At their head, Commander Typhon roared his men onwards. Like his warriors, he was protected by the massive bulk of his modified cataphractii armour, painted white in the colours of the Death Guard. Rounded plates that heaped up higher than the top of his knightly helm protected his shoulders, his chest and gut encased in segmented slabs of ceramite, arms and legs sheathed in thick greaves and vambraces. Adamantium mail hung in sheets across the joints of his armour. The left arm of his suit was incorporated into the bulk of a reaper autocannon, its twin barrels spitting a rapid-fire hail of shells towards the Iron Hands, chewing through the ammunition belt like a starving dog devouring a strip of sinew. In his right Typhon held a manreaper, a wickedly-bladed power scythe, symbol of his rank, and a smaller copy of the weapon wielded by his primarch, Mortarion. The glow of its power field shone a sickly yellow light on the white Terminators around him.

Heavy support Terminators backed up the twenty warriors of the spearhead, their cyclone launchers sending showers of missiles over the heads of their companions, detonations cracking the plastite sheathing of the tunnel walls and tossing silver-and-black armoured legionaries into the air. Combi-bolters spat rapid-fire rounds as the Grave Wardens continued to close, marching unharmed into the teeth of the enemies' fire.

The Iron Hands fell back, unable to match the Grave Wardens with their heavier armour and weaponry, but progress was slow. Ghrusul had reported entering Tower Eight twenty minutes earlier, yet Typhon was still two interchanges from breaching the tower from below. He was expecting word from Vioss at any moment, telling him that the Dark Angels were in orbit, but until then he was determined to press on with the attack.

The leading squads of the Grave Wardens were within fifty metres of the end of the interchange held by the Iron Hands when Typhon's helm crackled with the signal of an incoming comm-link. Rather than the sibilant whisper of Vioss, he heard a deep voice filled with authority that caused him to involuntarily stop in his tracks. Around him, the rest of the Death Guard were similarly immobilised and the fire from the Iron Hands died away within seconds.

'The world of Perditus Ultima is under the protection of Lion El'Jonson of the First Legion,' boomed the message. 'You are to immediately cease all warring and quit this planet. Any resistance will be met with ultimate force and there will be no prisoners taken. Failure to comply with my demands will result in your immediate destruction.'

As if breaking from a trance, Typhon staggered forwards a step, almost losing his footing. Only in the presence of Mortarion had he ever experienced anything like the reaction he had just felt and he quickly realised that it was not just the Dark Angels that had arrived: their primarch was with them. He could sense the unease of his warriors as they came to the same conclusion, and the advance that had shuffled to a halt was slowly turning into a withdrawal. Ahead, the Iron Hands were backing away from their positions too, cowed by the same tone of authority that had pierced the minds of the Death Guard.

Typhon gritted his teeth and shook his head to rid himself of the fugue that had descended on him following the Lion's proclamation. He knew that there was something else at work here, not just the innate command of a primarch. Typhon opened up his mind to the warp, sensing the waves of energy that were part of, yet separated from, everything in the material universe. When he had been a member of the Librarius his powers had been considerable. Mortarion's hatred of warpcraft had finished Typhon's exploration of his other nature when the Dusk Raiders became Death Guard, and so he had committed himself to becoming First Captain. Now, with the encouragement of darker sponsors, Typhon had once again embraced the warp-born side of his powers, learning far more about the universe and its mysterious ways than he had ever thought possible.

It was this that had first brought him in contact with the Father, and it was his warp-self that now detected the gentle interplay of energies being directed at the surface of Perditus Ultima. It seemed the Lion was no longer impressed by the Council of Nikaea's decision either and had allowed his Librarians to reclaim their birthright.

With this knowledge, Typhon was able to extend a little of his will, seeking a means to block the resolve-weakening presence of the Dark Angels Librarians. Despite his personal prowess, he was up against several trained minds, and so he turned to that shadowy force that had accompanied him these past years. He asked the Father for help, and help was granted.

With a surge of psychic energy buzzing through him, its touch like the tread of a thousand tiny insects in his mind, Typhon cast a pall of shadow over his Grave Wardens, shielding them from the assault of the Dark Angels psykers. Almost immediately they ceased their withdrawal and turned to him, expecting orders.

'Fools!' he rasped, pointing his manreaper at the retreating Iron Hands. 'Now is not the time to step back, now is the time to attack! Slay them all.'

In a darkened chamber in the bowels of the Invincible Reason, the Lion stood between four of his Librarians, listening to their murmuring voices. All of the psykers had donned their old ceremonial robes of blue, their faces hidden by the shadows of the cowls pulled over their heads. It was better that this was kept from the sight of the ordinary battle-brethren. Confusion and hearsay could breed superstition faster than any explanation could thwart it.

Corswain stood to one side, his agitation audible as he shifted his weight from one foot to the other and back again, his armour creaking with each movement. The Lion ignored his seneschal's discomfort. This way was better, cleaner. If the Death Guard and Iron Hands could be forced to parley without fighting, it would be in the best interests of the Dark Angels.

The Lion sensed Corswain straighten and he turned his gaze upon the seneschal.

'It's not working, my liege,' said Corswain, sounding relieved by the fact. 'Sensors show that the Iron Hands are retreating from a renewed Death Guard assault. They are being pushed back into the main facility.'

'I warned them,' snarled the Lion. 'None will doubt my authority.'

'Shall I signal Captain Stenius, my liege?'

'Yes. If the Death Guard do not comply with my wishes, Magellix station will be obliterated. Tell Stenius to launch the torpedo.'

VII.

Slashing the yellow-gleaming blade of his manreaper across the chest of an Iron Hands sergeant, Typhon shouldered his way through the doorway leading out onto the courtyard in front of Tower Eight. He was swathed by the shadow of the eight great Mastodons, their gun sponsons silenced and their canopied driver's cabins emptied by the boarding actions of his Grave Wardens, who were now pressing on towards Tower Three. From there the main gate of Magellix would be within reach.

'Commander, we have received a signal from the fleet.' Vioss's tone was urgent.

'Why have they not yet attacked the Dark Angels?' snapped Typhon as he lumbered up the gentle slope of the courtyard not far behind the line of his advancing warriors.

'The Dark Angels have positioned themselves between our ships and the enemy. Any attack against them will allow the Iron Hands to move around the flank of the flotilla. We have more urgent concerns, commander. The Lion's battle-barge has launched a torpedo towards Magellix.'

'A bluff,' Typhon replied instantly. 'The Lion will not destroy Magellix any sooner than I or my counterpart in the Iron Hands. The contents of that facility are too precious to risk destruction. Continue the attack.'

'Are you sure, commander? We have detected a cyclotronic warhead. It will obliterate everything at Magellix and a hundred kilometres around. It will destroy Tuchulcha as well as us. The fleet also reports detection of seven more Dark Angels vessels heading in-system.'

Typhon paused, a thought occurring to him. He voiced his doubt to Vioss.

'What if the Lion does not desire Tuchulcha, but merely wants to prevent us from gaining possession?'

'Commander, we cannot risk guessing the Lion's intent. We must pull back. We can achieve nothing if we are annihilated.'

Growling to himself, Typhon activated the company-wide comm-stream. He snapped out a series of commands, pulling back his warriors from their final assault on the main gate. Instead, he established them in positions overlooking the central tower of Magellix and guarding the tunnel network beneath. When he was finished issuing orders, he switched his comm-unit to a general broadcast.

'Happy now, Lion of the First?' he snarled. 'I will respect any ceasefire observed by the enemy. Know now that you intrude upon the business of the Death Guard Legion, and it will go poorly for you.'

Surprising Typhon he had expected no reply to his invective the comm crackled with a return signal. It was the same resonant voice as before the Dark Angels primarch. It was too late to reconsider his scornful words, and his disdain would not allow him to offer any apology for them even if the Lion demanded it.

'Look to the western skies.'

Typhon turned his gaze as instructed. He saw a flash of light in the upper atmosphere, and what appeared to be a suddenly-spreading electrical storm set the jade clouds roiling. Seconds ticked past before the crack of the torpedo's detonation reached the commander's audio pick-ups.

'You are to pull back all forces from Magellix station. I will grant you safe passage back to your vessels. You, Captain Typhon, will remain at Magellix with a bodyguard of no more than one hundred warriors to attend a parley under my aegis. The rest of your force will remove themselves to two hundred thousand kilometres from orbit. Failure to comply will result in your destruction. The same conditions have been transmitted to Captain Midoa of the Iron Hands.'

The link cut before Typhon could respond, not that he had anything to say in the face of such a bald ultimatum. He watched the dark clouds of super-heated gases expanding like a blue stain across the western sky and realised that the Lion did not make empty threats. For the moment, his mission was compromised, but that did not mean he had to abandon his objective entirely; he had means unknown to the Dark Angels.

'Vioss, one hundred of the Grave Wardens to form an honour guard. All other forces are to return to orbit. Have the remaining Grave Wardens embark on Terminus Est and I want you to take personal charge of the dearthfield. We shall allow the Lion to believe he is master of Perditus for the time being.'

'I understand, commander. The Grave Wardens will re-arm and repair in preparation for the next offensive. We will not suffer defeat here.'

The fog covering the inner courtyard of Magellix station was dispersed by the plasma and steam of a descending Stormbird. The eagle-like craft put down, its landing struts taking the weight as the dust settled around it and the mists began to seep back between the perimeter towers.

There were already a thousand Dark Angels arranged by company between the arriving ship and the main gate of Magellix. To one side of the force waited the Death Guard while the Iron Hands were guarded behind a cordon on the opposite side of the open space. Only Typhon and Midoa had been permitted to approach the Lion's landing craft, two armoured giants amongst a gaggle of a dozen Mechanicum acolytes dressed in red robes, the heads of all but two encased within breathing domes; those other two had rebreather attachments inserted into their faces and chests and required no further assistance in the thick Perditus atmosphere.

The Lion stepped out on the descending ramp of the Stormbird with Corswain to his right and the recently-arrived Captain Tragan to his left. Behind came a number of banner bearers and other attendants carrying such articles of Caliban as usually accompanied the primarch; plaques, goblets, crowns, shields and other items associated with the Lion's multitude of ranks and duties. Behind them came the cabal of Librarians, now numbering six from the fleet mustering in orbit, their blue robes flapping in the slow but strong breeze the higher-pressure air of Perditus turned even a sluggish gust into a wind that could bowl over a normal man. As one the Dark Angels silently lifted bolters, heavy weapons or swords in salute to their commander-in-chief.

The Lion needed no helm, though the air was acrid in his throat and made his lungs feel stretched by its weight. He wanted to impress upon all present that he was a primarch, with the force of an entire Legion to command, and not just any Legion; the Dark Angels, the First Legion. His standard bearers took up station on either side of the route to the main gate, the Lion's many titles shouted through their external address systems.

The Lion's armour had been polished to a gleam, the black enamel as glossy as midnight oil alloyed with diamond, the gold shining like the heart of a star. A scarlet cloak draped from his shoulders, its train five metres long, kept aloft by the artifices of Caliban; ten suspensor-floating devices wrought in the shape of short blades etched with the names of the Knightly Orders of his homeworld. On his left hip the Lion wore his greatsword, Adamant, its ruby-encrusted pommels and gold-chased hilt and crosspiece glittering as brightly as his armour. Below the right side of his breastplate the Lion's belt was hung with six cylinders each the size of a man's forearm, bound with platinum, the dull red leather cases containing the Proclamations of Caliban; the first laws decreed by the Lion after his ascendancy to command of the Dark Angels, swearing Caliban to the service of the Emperor for eternity.

Sweeping down the ramp with his entourage keeping step as best they could, the Lion advanced on the waiting Mechanicum dignitaries. They introduced themselves in ascending order of rank, so that the Lion instantly dismissed the first eleven shrivelled, half-machine men and women and focused all of his considerably intimidating attention on the last: High Magos Khir Doth Iaxis, Overseer of Magellix and Custodian of Tuchulcha, as his heralds attested.

Iaxis was a tiny man, perhaps no more than a metre tall, taken to be a child attendant by the Lion until the magos had pulled back his hood to reveal a near-conical head and ageing, pinched face. The back of the magos's skull was extended by a series of segmented plates that came to a rounded point and moved strangely of their own accord, contracting and expanding slightly, perhaps as mood or effort occupied the Mechanicum priest. Thin bony fingers jutting from veined hands rubbed and entwined together, almost hidden in the cuffs of Iaxis's heavy sleeves, and his slight shoulders were no wider than the Lion's greave. If the diminutive tech-priest felt at all threatened by the giant looming above him and the Lion could have easily crushed him with his foot like a titan of myth the magos did not show any hesitation. His thin, reedy voice was almost muted by the bubble of the breather dome encompassing his small head, but the words were spoken with authority and precision.

'We are pleased to welcome you again to Perditus Ultima, Lion of Caliban,' said Iaxis, nodding his head inside the breather dome. 'Please follow me.'

The Lion felt a moment of impatience, expecting to be forced to check his stride in the company of the minuscule Iaxis, but his fears were misplaced. As the magos's entourage dispersed, they revealed a set of mechanical legs, which Iaxis ascended quickly by means of a narrow ladder at their rear. Placing his own legs inside the struts of the machine's pelvic arrangement, his robe rucking up briefly to reveal pale, wiry legs interlaced with reinforcing struts, Iaxis settled into the ambulator. With a hiss of actuators, the legs straightened, bringing Iaxis almost to the height of the Lion's shoulder. In the presence of his minions, Iaxis would have been above them all, but the primarch still stood taller than the mechanically-bolstered magos.

As they walked to the main gate the Lion became aware of a silver-and-black shadow hovering close to Corswain's shoulder: Captain Midoa. Glancing to his left, the Lion saw Typhon walking shoulder-to-shoulder with Tragan. The Lion ignored the other captains until they were all inside the entrance chamber behind the main gate. Once inside, the Lion turned and addressed his 'guests'.

'Captain Typhon, Captain Midoa...' The Lion was not sure what he was going to say to them. They were an inconvenience at the moment, but as he had explained to Corswain aboard the Invincible Reason, it did not suit to make hasty or arbitrary judgements about the loyalty and agenda of others. He instead addressed Iaxis. 'Magos, please convey the two captains to a suitable part of the facility where they may await my return. Little brothers, you will watch them for me. Captains, I remind you that all of Magellix is under the protection of my aegis. Do not think for a moment to dishonour me.'

With that matter perfunctorily dealt with, the Lion turned his back on the two captains and continued across the gate hall. The chamber sloped downwards slightly, the far end broken by three archways, each leading to a set of moving steps that descended further into the bowels of Magellix.

'The door on the right, primarch,' prompted Iaxis. 'Let me show you what all of this fuss is about.'

Most of the Mechanicum facility had not existed the last time the Lion had been on Perditus Ultima, but the tunnels beneath were familiar to the primarch. Though they were now sheathed in plasteel struts and plastite board, the meandering passageways were etched into the Lion's memories, so that once they disembarked from the fourth internal conveyor, some half a kilometre below the surface, he was able to find the path unerringly towards the cavernous chamber where the machine was kept.

The last time he had walked these tunnels, frenzied machine-cultists had been dying by his hand. The people of Perditus had been enslaved to the machine and died in droves to the guns of the Dark Angels and the newly-renamed Death Guard. The Lion's first encounter with Mortarion, a tense affair that had ended with neither primarch liking the other, had taken place only three months earlier, and the two Legions had been fighting side-by-side as a display of unity for the Emperor. The Perditians had howled praise to their inanimate overlord even as they perished. Now the tunnels rang only with the boots of the primarch and the thud of Iaxis's walking apparatus.

Coming to the central cavern, the Lion found further passage barred by an immense doorway, emblazoned with the symbol of the Mechanicum. Iaxis stalked forwards on his artificial legs and pushed a hand towards a reader-plate set into the metal beside the portal. The Lion's sharp eyes glimpsed a design on the wrist of the tech-priest as he extended his arm; a faint outline almost indiscernible from the rest of the overlying skin. The primarch knew it for what it was immediately: an electoo, a hidden mark that could be realised into being by a pulse of bio-electricity. The Mechanicum made wide use of them as did some of the more secretive orders on Caliban and many other societies throughout the Imperium but the Lion had never before seen the design concealed on Iaxis's arm. It was of a stylised dragon, wings furled, coiled tightly about itself so that its neck merged with its body and its head lay alongside its tail.

'Your electoo, what is its significance?' the Lion asked as door locks rumbled into the walls and a heavy clanging sounded from within the door itself. 'I thought myself learned in the customs of the Mechanicum, but it is a device I do not know.'

Iaxis inhaled sharply and glared at his wrist as if in accusation. His expression mellowed after a moment, becoming one of embarrassment rather than shock as he regarded the primarch with yellowing eyes.

'A childish totem, Lion, nothing more,' said Iaxis. He paused and a moment later the dragon appeared prominently on his withered flesh, glowing a deep red. 'The Order of the Dragon, something of a defunct sect now, I am pleased to say. It is remarkable that you could see that pigmentation beneath my skin, I had quite forgotten it.'

The door opened with a hiss of venting gases, swinging inwards to reveal the cavern etched into the Lion's memories. Much had changed, but it was unmistakably the same place. The vaulted ceiling, nearly seventy metres high and banded with rock strata of many colours, was pierced now by rings bearing heavy chains from which hung guttering gaslights. The walls, nearly two hundred metres apart at their widest, were obscured behind panels of Mechanicum machinery and devices, so that the bare stone was hidden behind banks of dials and levers, flashing lights and coils of cabling and pipelines.

Gantries and walkways, steps and ladders were arranged around the device itself, with sensor probes, monitoring dishes and scaffolding further enmeshing the centre of the warp device. The thing itself was still there; the sentience, or at least semi-sentience that had enslaved a whole star system hanging in mid-air like a world in the firmament. It was a perfect sphere of marbled black and dark grey, with flecks of gold that moved slowly across its surface. Ten point six-seven metres in diameter the Lion remembered the Mechanicum's first measurements exactly it was made of an unknown material, impenetrable to every sensor, drill and device the Mechanicum had brought with them.

The Lion knew that the thing was regarding him with some alien sense. He was not sure how he could tell, nor how the warp device could sense him in return, but the fact remained that he was convinced it saw him this time as much as he had been convinced the first time he had entered this hall. On that occasion several hundred rag-clad Perditians had died in the next few minutes, unwilling or unable to lay down their primitive weapons, forced to defend their demigod to the last breath and drop of blood.

There was something else different, at first unnoticed amongst the rest of the Mechanicum clutter. Two protuberances now extended from the sphere, one at each pole, each only a few centimetres long. The rounded nodules touched against circuit-covered plates stationed above and below the device, which in turn were linked by a dizzying web of wires and cables to the surrounding machines. On a mat in front of the orb lay a small boy, aged perhaps no more than seven or eight Terran years. He lay immobile on his side, eyes unblinking, as stiff as a corpse, which he might have been were it not for the gentle rise and fall of his chest; the Lion could hear the boy's heart beating ever so slowly, and could smell sweat and urine on the air.

A pipe extended from the boy's back, and another from the base of his skull, joining him with the mechanical array surrounding the warp engine. As soon as the Lion's eyes fell upon the boy, he sat up, moving jerkily like a badly-controlled marionette. The eyes were glassy, the limbs moving stiffly. With a glance at the alien orb, the primarch saw the golden motes were moving more swiftly than before, forming brief patterns in the dark swirl.

'You have returned.' The boy's voice was flat and devoid of emotion, his face featureless. A hand raised and waved erratically.

'It talks now?' said the Lion, the words half-snarled as he turned on Iaxis. The tech-priest shrugged.

'We could not discern anything of its construction or workings, but it seemed likely that it had some means to communicate with the Perditians before we were forced to wipe out their society. It took us nearly thirty years simply to devise this crude interface. We have learnt a lot from Tuchulcha. It is very cooperative, if a little enigmatic and, well, alien.'

'I hear too,' said the boy. 'You seem displeased.'

'You remember me,' said the Lion, before he could stop himself. He glared at Iaxis. 'Why the boy? We fought to rid Perditus of slaves and you have given it another.'

'Oh, that,' said Iaxis with a dismissive wave of the hand. 'It's just a servitor, Lion. We tried all manner of computational, logarithmic and cipher-based languages, but none of them worked. When presented with a servitor, though, it was able to tap into the established neural interface in only a few days.'

'What a coincidence,' said the Lion.

'There is no coincidence. I was designed to assimilate with the human form, Lion. May I call you Lion? I overheard the magos use it. Is that the correct form of address for one such as yourself?'

The primarch wanted to ignore the device's questions, but the boy's voice lingered in his thoughts.

'What are you?' said the Lion, stepping forwards until he was within arm's reach of the puppet-servitor.

'I am Tuchulcha, Lion. I am the everything. I believe the magos and I are friends, though he sometimes grows angry with me. I try to remain patient with his outbursts.'

'I asked what you are, not who you are. Curse you, what am I saying? You are a machine, a sophisticated machine and nothing more.'

'I am everything, Lion. Everywhere. I was once Servant of the Deadly Seas. Now I am the Friend of the Mechanicum.'

'You are dangerous,' said the Lion. 'A war is being waged for possession of you. I should destroy you and save much turmoil and bloodshed.'

'You cannot destroy me, Lion. Not physically, nor do you desire it. All things desire to possess me. The one they call Typhon dreams much about me. The mind of the other, Midoa, is closed to me. It contains too much iron for my liking. You... You are neither open nor closed. You scare me, Lion. It was not until you came that I knew what fear was. Your return scares me, Lion. I do not wish to be destroyed.'

It was hard not to imagine the words being uttered were from the boy, but the Lion forced himself to focus on the glistening orb rather than its animated avatar.

'Iaxis, my puppet needs more nutrients.' As Tuchulcha said this, the boy's bladder emptied, sending a watery stream down his leg to puddle on the plasteel floor. 'My apologies, Lion. I have not yet mastered the basic functions of this form. Its pathways were underdeveloped.'

'It is the third servitor we have had to attach,' explained the tech-priest. 'The previous ones aged unnaturally, hence the youth of this specimen. We are hoping it will survive for a few years longer than the previous interfaces.'

'You seem to know a lot about what is happening on the surface,' said the Lion, suppressing the distaste he felt at Iaxis's uncaring attitude to the expenditure of human lives, even if they were unthinking servitors.

'They pass through me, and I come to know them,' said Tuchulcha. 'Their minds touch upon mine. Yours does too, but it is far too heavy to carry. How do you cope with such a burden?'

'My intellect?' said the Lion.

'Your guilt.'

The Lion did not answer straight away, not trusting himself to reveal something in front of Iaxis that he would rather remained inside his own thoughts.

'What use is it?' he demanded of Iaxis, turning away from the boy-puppet. 'It was agreed with the Mechanicum that Perditus Ultima and the device were spared only because you thought it might have some purpose we could harness for the Imperium.'