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 shelling. The square was a mass of people fleeing the wrath of the Space 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 Titan’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 amusement 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 glassy 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 possiblefutures. 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 banal as a bolter shell.

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 grass. “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 grass 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.