Every single warrior, friend and foe, had been struck down by that terrible explosion, the shockwaves spreading through the city like an earthquake. What buildings were left standing after the punishing barrages were brought down and cast to ruin by its force.

The light diminished as whatever vessel had torn the veil between worlds open was destroyed. Ahriman saw a blazing humanoid form lurching drunkenly on the horizon, like a burning wicker man set alight by highland savages to please their heathen G.o.ds of the harvest.

A flickering image appeared in his mind, a taunting vision of a future he could not change, and he closed his eyes as the towering battle engine that had fallen on Coriovallum died for a second time. Ahriman had seen where it would fall, but had no desire to watch the destruction of the Corvidae pyramid.

He heard the earth-shattering sound of screaming steel and breaking gla.s.s, the sound of all that might yet be known reduced to ashes and lost hope. The monstrous battle engine crashed to earth, sending another powerful tremor through the city as the Pyrae temple exploded in a simultaneous fireball.

Ahriman stared in open-mouthed horror at this trifecta of destruction. This was the death knell for his Legion. The perimeter was no more. The entire north-west sector was gone, and the enemy would pour through in unstoppable numbers as soon as they realised the boon they had just been handed.

The lull created by the destruction balanced on a knife edge, and the Thousand Sons were the first to recover their wits. As the s.p.a.ce Wolves picked themselves up, the Scarab Occult struck with a dreadful torrent of lethal powers. Blazing cones of lightning seared the enemy, gleeful arcs of crackling power leaping from warrior to warrior. Hissing fire swept through the streets, devouring all it touched, melting stone and ceramite and flesh in the inferno of its incredible heat.

At first, Ahriman dared to hope that the surging aetheric energy might yet be their salvation, but his hopes were dashed seconds later. A warrior ten metres to his left screamed in abject horror as his body erupted in a ma.s.s of hideous growths. His armour buckled and cracked as his mutant flesh spilled out with horrid fecundity. Another warrior followed, seconds later, his body borne aloft on a seething geyser of blue flame that consumed him in the time it took to draw breath.

Yet more hideous changes were being wrought upon the Thousand Sons, vile appendages erupting from splitting armour plates, squamous limbs and rugose growths pushing like jelly from gorgets and through bullet wounds with grotesquely wet sounds.

Warriors screamed and fell to their knees as decades of suppressed flesh change ripped its way to the surface. Dozens were falling prey to its malign influence with every second, and the cries of horror were not confined to the s.p.a.ce Wolves. The Spireguard fell back from their erstwhile allies, as the degenerate things the Thousand Sons were becoming turned on them with mindless hunger to feed their rampant growth.

"Everyone back!" shouted Ahriman, knowing that this position was lost.

Those Thousand Sons who resisted the flesh change took up the cry, and even a cursory glance told Ahriman they were the oldest and most experienced warriors of the Legion. He was glad to see that Sobek was amongst them. With the remnants of the Spireguard, he and his Practicus led the survivors back through the ruined edges of Old Tizca, moving swiftly along sh.e.l.l-cratered streets and avenues filled with fire and rubble.

Ahriman checked his weapon loadout, seeing he had a mere five magazines remaining to him. His heqa staff was still a potent weapon, its length crackling with invisible lines of force. He willed it to powerlessness, for he dared not wield it with so much wild energy filling the air. He would have need of his staff before the end of the fight, but he forced all thought of its use from his mind until he needed it most.

No sooner had he quelled his powers than he sensed a ghostly presence probing the aether around him, a questing tendril that spoke of another mind seeking his. Ahriman felt the primitive cunning of a hunter, the patience and animal circling that spoke of long years spent on the frozen tundra with nothing to warm the flesh but fur torn from the still warm corpse of native prey-beasts.

It took no great skill to recognise the presence, for he had swum the Great Ocean with this seeker. Ohthere Wyrdmake was hunting him, and Ahriman allowed his aetheric presence to bleed into the air, psychic spoor to draw the Rune Priest to him.

"Come find me, Wyrdmake," he whispered. "I welcome it."

Ahriman led his tattered remnants through the ruins of his beloved city, picking up scattered warbands of sh.e.l.l-shocked Thousand Sons warriors from the west and east as they converged on Occullum Square. He counted several hundred close by, and only hoped there were others deeper in the city, for they would need more if they were to hold the s.p.a.ce Wolves and Custodes at bay.

Occullum Square was just ahead, and as Ahriman saw the toppled, bullet-ridden statues of a number of lions, he suddenly recognised where his line of retreat had led: the Street of a Thousand Lions. He almost laughed as he saw that the leftmost lion in the street had escaped destruction, its golden hide as polished and pristine as if it had only recently left the sculptor's workshop. He paused in his flight from Old Tizca and reached up to touch the rearing beast.

"Maybe you really are lucky," he said, feeling foolish but not caring. "I could use some of it if you have any to spare."

"Superst.i.tion doesn't suit you," said a voice behind him, and Ahriman smiled with genuine relief as he saw the limping form of Hathor Maat in the midst of the retreating warriors. Ahriman ran over to meet him, and they embraced like devoted brothers.

"What happened?" asked Ahriman, turning from the rearing lion.

"The Wolf King," replied Hathor Maat, and Ahriman needed no further clarification.

"Phosis T'kar?" he asked as they set off south once more.

Hathor Maat looked away, and Ahriman saw the dreadful waxiness to his skin, an unhealthy pallor that was as alien and abhorrent to a biomancer as any gross mutation. To see the normally absurdly handsome Hathor Maat so broken was almost as unsettling as anything Ahriman had seen in the course of this nightmarish battle.

"The flesh change took him," said Hathor Maat, the terror of what he had seen haunting his eyes. "Valdor of the Custodes killed him, but I think Phosis T'kar let him. Better death than to live as a monster. Auramagma is gone too."

Ahriman had no special regard for Auramagma beyond his status as a fellow captain, but he grieved the loss of Phosis T'kar. If he lived through this horror, he would grieve his friend in the proper manner, and once again he realised that only death allowed him to recognise a fellow warrior as a true friend.

He forced his grief for Phosis T'kar down, keeping to the lower Enumerations to close himself off from the loss. He wondered how the loss had affected Hathor Maat. Coagulated blood coated the left side of Maat's skull, but that was the least of his concerns. His skin shimmered with an internal light that rippled with the urge to change, and Ahriman hoped the vain warrior would resist the temptation to use his powers to stop it.

"Where are we going?" gasped Hathor Maat as they ran.

"The second line of defence," said Ahriman.

"What second line of defence?"

"An east to west line between the pyramids of the Athanaeans and the Pavoni, with the Great Library at its centre and the Pyramid of Photep at its back."

"That's a long line," pointed out Hathor Maat.

"I know, but it is shorter than the last one. If we can hold it long enough to allow the bulk of Tizca's citizens to reach whatever safety the Pyramid of Photep can provide, then we'll have achieved something worthwhile."

"It's not much."

"It is all we can do," said Ahriman, running south while casting hurried glances over his shoulder as he heard the first signs of pursuit. The horrific sp.a.w.n many of his warriors had become would delay the s.p.a.ce Wolves, but Russ' butchers would carve their way through them soon enough. Ahriman swallowed his anger, knowing it would do no good, for it had too many targets. He had anger enough to last a thousand lifetimes.

Anger at the unthinking violence Russ and the Custodes had unleashed against them.

Anger at the death of so many brave warriors who deserved better.

Anger at how easily he had allowed himself to turn away from asking questions that needed to be asked.

But most of all, anger at Magnus for leaving them to face their doom alone.

AHRIMAN LED HIS warriors across Occullum Square, past the great urn-topped column at its centre, which, like the lion, had miraculously avoided destruction in the sh.e.l.ling. The square was a ma.s.s of people fleeing the wrath of the s.p.a.ce Wolves and Custodes, for the blades and bullets of the enemy were uncaring which of the city's inhabitants they cut down. Panicked people poured into the square from all its radiant streets, heading towards its southernmost exit, a wide avenue incongruously named the Palace of Wisdom.

A shattered arch lay in ruins around its entrance, and toppled columns lay strewn next to shattered statues of long-dead scholars of the Athanaeum. The gold-skinned form of Prospero's Great Library was barely visible through the smoke pouring from its shattered sides, and beyond it, the gleaming crystal form of Magnus' great pyramid reared over all.

More survivors of the aetheric burst and the t.i.tan's fall poured into Occullum Square, and Ahriman estimated at least three thousand warriors of his Legion. Compared to the strength that had been fighting at the start of the battle it was pitifully few, but it was more than he had expected. How many, he wondered, had fallen to the enemy, and how many to the flesh change running rampant through their ranks?

He pushed the question aside. It was irrelevant, and he had more important matters to deal with. He ran towards the Palace of Wisdom, leaping a marble representation of the mad Scholar Alhazred with Sobek and Hathor Maat to either side of him. The Palace of Wisdom was paved with black marble slabs, each one engraved with an uplifting, cautionary or instructional quote from some of the Great Library's most prominent contributors. Dust, rubble and panicked citizens of Tizca obscured many of the slabs, but sensing a cosmic order to those that remained, Ahriman kept his eyes fixed on the ground as he ran.

The first slab bore the words: without wisdom, power will destroy the one who wields it.

Knowing there was no such thing as coincidence, Ahriman focussed his attention on each slab as he ran across it.

Seekers desire power but not wisdom. Power without wisdom is dangerous. Better to have wisdom first.

Those who have knowledge do not predict. Those who predict do not have knowledge.

If you abuse power, you will be burned and then you will learn. If you live.

And lastly, Ahriman smiled with grim amus.e.m.e.nt as he saw a slab that read, Only the fool wishes to go into battle to beat someone for the satisfaction of beating someone.

The significance of these words was not lost on him and he wondered why he had been chosen to see them. There was little he could do to affect the destiny of the Thousand Sons.

Only one being on Prospero could do that.

THE THOUSAND SONS formed up on the edges of the once-verdant park of the Great Library. Hathor Maat and Sobek formed the Scarab Occult and ragged warbands in a line of armoured bodies across the park, their guns pointed to the north. A mist of burnt sap and greenery clogged the air, and the smoke from the ashen forest hung low to the ground, like a noxious fog swirling around their ankles. The Great Library was in ruins behind them, its structure now barely recognisable as a pyramid. Its gla.s.sy sides were bathed in golden light from the fires raging throughout its many galleries. Its tip had caved in, and smoke poured from its collapsed summit like billowing spurts of lava from a steep-sided volcano.

Ahriman started as a memory overlaid his vision of the Great Library.

"What?" asked Hathor Maat, seeing his look of consternation.

"It wasn't Nikaea at all," said Ahriman. "I did not see the volcano at all. It was this... I saw this."

"What are you talking about?"

"On Aghoru," said Ahriman with mounting horror, "I foresaw this, but I did not recognise it. I could have warned Magnus. I could have stopped this."

Hathor Maat dragged him around.

"If you saw this, it was going to happen no matter what. There's nothing you could have done," he said.

"No," said Ahriman, shaking his head. "It doesn't work that way. The currents of the future are all echoes of possible futures. I could have-"

"Could have is irrelevant," snapped Hathor Maat. "You didn't see this. Neither did Amon, Ankhu Anen or Magnus or anyone else in the Corvidae. So stop worrying about what you didn't see, and pay more attention to what's right in front of you!"

The sheer incongruity of Hathor Maat giving him advice broke the spell of immobility that held him. Ahriman nodded and turned from the Great Library, concentrating his attention on their defensive line. It was easier to defend than the last one, but still too long for the number of warriors they had left.

The parkland was filled with ruined pavilions, low walls and decorative follies. On any normal day, its paths and arbours would be filled with citizens and scholars reading words of wisdom beneath the balmy sun. Ahriman had spent many a day beneath its green and pleasant boughs, ensconced in many a quaint and curious volume of forgotten lore. Now he looked on its walls, fallen trees, broken plinths and shaded hollows as defensive positions.

"We'll hold one attack, maybe two," he said, reading the contours and angles of the devastated park. "Then we must fall back to the Pyramid of Photep."

"I think that might be optimistic," said Hathor Maat, as Leman Russ led six thousand Astartes and Custodes towards their position like the closing jaws of a hungry wolf. It was a sight calculated to break the defenders' will, but Ahriman recalled a quote from a leader of Old Earth and lifted his voice so every Thousand Sons' warrior could hear him.

"The patriot volunteer, fighting for his country and his rights, makes the most reliable soldier on Earth," he cried, pulling his bolter in tight to his shoulder. He aimed along the top of the gun and smiled without humour as he saw Ohthere Wyrdmake slotted neatly between the open sights of his bolter. The Rune Priest was way out of range to take the shot, but Ahriman had no intention of ending their enmity with something so ba.n.a.l as a bolter sh.e.l.l.

He handed his weapon to Sobek and turned to Hathor Maat.

"Remember on Aghoru when I told you we allowed our powers to define us, and that we needed to learn to fight as Astartes again?"

"Of course," said Hathor Maat, confused as to Ahriman's meaning. "What of it?"

"This is that moment," said Ahriman, removing his helmet and dropping it to the blackened gra.s.s. "Fight these dogs and show them that of all the mistakes they have ever made, underestimating us will be their most heinous. Fight them hard, but no one must use their powers or it will be their undoing."

"What are you talking about? What are you going to do?"

Ahriman sat cross-legged on the blackened gra.s.s and gripped his heqa staff, its gold plated length and blue copper bands crackling with awakened power.

"Ignoring my own orders," he said, and closed his eyes.

AHRIMAN LIFTED HIS body of light from his corporeal form with a breath. The raging currents of the Great Ocean lapped close to the surface of the world, making the transition as easy as it had ever been. The force of the tides battering his subtle flesh was enormous, driven to fury by the heightened emotions at work within the cauldron of combat in the material universe.

The flesh change sought to claim him, but he forced it down, knowing this was probably the last time he would fly the Great Ocean. He rose higher, seeing the blazing, serpentine curve of Tizca's outline and the red haze that lay over its once-proud architecture.

"Such hatred," he whispered. "Did we ever deserve so much?"

He flew from the park of the Great Library, fighting to hold his course in the face of battering currents and dangerous breakers. He felt the raw wound where the aether had broken through in the north-west, hearing the echo of a soul in torment as it was torn apart by the rapacious void-predators who gathered around the pulsing wound in the hope that it would open once more.

The line of enemy warriors shone with brilliant vividness: golden and red, vibrant and so sure of their purpose. They could not see how they might be wrong. Ahriman saw a mysterious cloud of deception lying over them and pitied them their ignorance.

"If you knew how you had been betrayed, you would join forces with us and end this."

Darkened shrouds hung over the advancing warriors and tanks, areas of dead s.p.a.ce where Sisters of Silence guarded the host's captains. Ahriman avoided them, knowing he would be hurled back to his body should he venture within such a hateful darkness. His foeman would never set foot within such darkness, for he was as hypocritical as the rest of them.

Ahriman smiled as he saw Ohthere Wyrdmake, so proud, so arrogant and so filled with anger that it was a wonder he could function as a human being. As much as he told himself he did this for his Legion's survival, Ahriman was forced to admit he was going to enjoy this mission of revelation.

He reached down with ghostly hands and wrenched Wyrdmake's body of light from his flesh, tearing up with such violent suddenness that the Rune Priest's armoured limbs went as rigid as a fresh-carved statue. His comrades and acolytes rushed to his aid, but Wyrdmake was beyond their help now.

Ahriman released his nemesis as his shimmering form took shape, coalescing into a bright replica of the man below. His aura blazed with shock and anger, but that quickly turned to sly hatred as he saw who floated before him.

"Warlock," spat Wyrdmake.

"Is that all you have for me, old friend?" asked Ahriman, folding his arms. "Insults?"

"I have sought you this day," said Wyrdmake.

"I know, I felt your clumsy pursuit. A Neophyte of Prospero could have sensed you. How did you acquire my psychic trace?"

"Your brother in the library gave you up," said Wyrdmake triumphantly.

Ahriman laughed.

"Is that what you think happened?" he asked. "If Ankhu Anen did so, it was because he wanted you to find me. He knew I would kill you if you did."

"I think not," said Wyrdmake, a golden staff appearing in his hands.

Ahriman shook his head and the staff exploded into shards of fading light.

"In this place, in this realm, do you really think we will fight like that?"

Wyrdmake hurled himself towards Ahriman, his hands outstretched like claws and his face transforming into that of a snarling wolf with its jaws poised to tear out his throat. Ahriman surged to meet him and they came together in a blazing explosion of power.

Wyrdmake clawed at him, but Ahriman moved like quicksilver, evading every strike and rising higher and higher into the Great Ocean. Spinning like intertwined spirals of genetic code, they streaked through the aether, Wyrdmake attacking in a frenzy of claws and snapping bites, Ahriman deflecting every strike with graceful precision.

"You are the same as me," he said, evading yet another raging attack.

Wyrdmake broke away from Ahriman's blazing form and shook his head, the wolf-form retreating within his shimmering flesh.

"I am nothing like you," he snarled. "My power comes from the natural cycle of birth and death of Fenris. I am a Son of the Storm. I am nothing like you."

"And yet you are not on Fenris," said Ahriman. "We call it by different names, but the power you use to call the storm and split the earth is the same power I use to scry the future and shape the destiny of my Legion."

"Is this all you have for me?" snapped Wyrdmake. "Lies? I can believe nothing you say."

"Lies?" said Ahriman. "Look at what you are doing to my world. I have no need of lies. The truth is my weapon."