'A Warlord?' responded Kasim, his excitement and fear manifesting in the Warhound's posture as it crouched close to the ground.

'No, my princeps,' said Vorich, staring in horror at the sight emerging from the howling dust clouds.

Kasim felt the chill of its shadow envelop him, and his skin flushed as he saw the enormous engine stride towards them, its every step rocking the very earth with its monstrous tread. A towering fortress of brazen red metal with black and silver etchings moulded on the great bastion towers of its legs, the enormous engine dwarfed the Warhound as a grown man would dwarf a babe in arms.

Arcing battlements crowned its immensity, the colossal, mountainous fortress engine unlike anything Kasim had seen before. He had heard the rumours and looked over the technical specs and blueprints of similar machines, but nothing had prepared him for the awesome spectacle of so gargantuan a war machine in the flesh.

Weapons capable of obliterating cities depended from its wide shoulders and its head was a grinning, horned skull of burnished silver.

'Imperator,' said Kasim.

Princeps Cavalerio scoured the Manifold for information, reading nothing through the barking, squealing hash of scrapcode fouling the airwaves. He could get nothing from Princeps Sharaq and feared the worst. Mortis was on the march, and Cavalerio wondered if Princeps Camulos was about to make good his threat of a coming storm.

His battle group was marching at flank speed towards their fortress and he could feel the ancient heart of Victorix Magna protest at the demands placed upon it. His own heart beat in time with the great machine and he felt a growing numbness spreading through his limbs.

Cavalerio fought against the sensation, willing both his mortal frame and the immortal might of his engine to keep going.

'Do you really think Mortis is about to attack Ascraeus Mons?' asked Moderati Kuyper.

'I don't know,' confessed Cavalerio, their words spoken through the link of the Manifold. 'I believe Camulos wants to drive our Legio from Tharsis, but this seems bold even for him.'

'Then perhaps this is the first strike in a larger war,' suggested Kuyper.

Cavalerio kept his thoughts close, remembering what Camulos had said at the Council of Tharsis.

Sides were being chosen and battle lines drawn all across Mars, and while Cavalerio couldn't bring himself to believe that the Titan orders were about to go to war, this manoeuvre of Mortis seemed deliberately calculated to rouse the ire of Tempestus.

Well, Indias Cavalerio was not about to rise to the bait of this provocation.

'I don't think they will attack,' he said. 'I think they want us to attack them, to fire the first shot so as to justify their retaliation.'

'Our warriors will only fire if they're fired on first,' said Kuyper.

Cavalerio thought of the engine commanders at Ascraeus Mons: Sharaq, Lamnos and Kasim. Sharaq could be trusted to understand the situation, but Lamnos and Kasim?

Their hearts were fiery and warlike, as was expected of Warhound drivers, but where heart and mind were in balance in more experienced warriors, Cavalerio feared what impulsive decisions they might make in the heat of the moment.

'Get me Sharaq's battle group,' he said. 'I need to make sure they know not to fire first.'

'Understood, Stormlord,' said Kuyper, returning his attention to breaking through the interference.

Cavalerio opened the Manifold link to Magos Argyre. 'How long till we reach the Mons?'

'Update: at flank speed, we will be within visual range of Ascraeus Mons in seventeen point four minutes. However, the reactor is running twenty-seven per cent in excess of what I believe it can safely handle at this time.'

'Increase reactor output,' ordered Cavalerio. 'I want us there in less than ten.'

'Warning: to increase reactor output beyond the current rate of—'

'I don't want to hear any excuses!' snapped Cavalerio. 'Just make it happen!'

The Imperator Titan had not come alone.

Two Warlords and a Reaver marched alongside it like the hangers-on of a scholam bully. Kasim could see no sign of a Warhound picket or skitarii escort, but with engines as large as this, what need had they of any skirmish screen?

The ground shook and cracked at its passing, and Kasim could only watch in mute awe as the mightiest war machine he had ever seen swept past him like an uprooted hive on mountainous legs.

'What do we do?' breathed Moderati Vorich.

What indeed? To fight such a monster was suicide, but its path would see it cross the Tempest Line in a little over nine minutes, and then they would have to fight it. They would be as ants against a bull-grox… but even ants could bring down a larger beast with enough numbers.

As his now active surveyors gathered what information they could on the might of the Imperator, Kasim knew that Tempestus had not the guns to defeat such a terrifying opponent.

'We follow it,' said Kasim. 'And we wait.'

'Wait for what?' asked Vorich.

Kasim looked down at his medallion, again wishing he could touch it. 'To see if this is the day we die,' he said.

Dalia screamed as the howling gale of psychic energy enveloped her, feeling it tear at her like a malicious hurricane. She heard screaming voices that clawed at the inner surfaces of her skull and whispers she could not possibly be hearing, but which sounded as clear as though she heard them lying on her bed in the middle of the night.

White light filled the chamber, the walls blurring in a rippling haze thrown off by the roaring column of silver that flared from the dome's apex and speared down towards Jonas Milus upon his throne.

She heard the metallic ring of the doorway closing behind her and spared a brief thought for Caxton and the others. Her robes billowed in the grip of powerful etheric winds, her skin raw and scoured by invisible energies that passed through her skin to the marrow and beyond.

Billowing ghosts of light swarmed the chamber, fleeting unnatural forms that defied description and which lingered uncomfortably in the darkest reaches of her imagination. Clouds of feelings filled the chamber: thunderheads of anger, zephyrs of regret, hailstorms of longing, hurricanes of love and betrayal.

Emotions and meaning surrounded her, though how such concepts could be given physical, visible form was a mystery to her. Dalia took a step into the chamber, feeling her will erode in the face of the primal energies that surrounded her and infused her at the same time.

'Jonas!' she yelled, the words fleeing her mouth in a gush of red. At first she feared it was blood, but the colour in the air vanished almost as soon as it had appeared. The noise filling the chamber was incredible, like the death scream of an entire race or the birth pangs of another.

All emotion and knowledge was here, and Dalia realised that this was the aether; this was the realm beyond the one her senses could consciously perceive. This was the source of all knowledge and the source of the greatest danger imaginable.

This was what she had allowed Jonas Milus to be exposed to.

The thought galvanised her steps, and she forced her way through the maelstrom of light and colour, feeling the energies unleashed by the psykers in the coffered ceiling bleed off as they began to die. She could feel their lives ending, dissipating into the cacophony of light and noise. She wept with sympathetic pain, feeling each death as a splinter of needle-sharp agony in her mind.

Dalia shielded her eyes as she drew closer to the dais, seeing Jonas Milus convulsing upon the throne, illuminated by the blinding light of the Astronomican. His head jerked spasmodically from side to side, his mouth a blur of motion as he screamed and yammered streams of words too fast to be understood.