Victorix Magna was an old machine, patched, repaired and refitted a thousand times in her long life of battle.

Her fiery heart was proud, but it was old like his, and Cavalerio wondered how many more marches they would take together.

In truth, the Victorix should still be in the care of the Legio artificers, but since the attack on Adept Maximal's reactor, Legio Tempestus could ill-afford to take chances with the remaining reactors clustered on the slopes of the crater or positioned along the canyons of the Ulysses Fossae.

Without those reactors, it would become increasingly difficult to keep the engines of his beloved Legio operational. Whoever had struck at Maximal had done so with great precision, destroying the reactor that provided the most power to the Tempestus fortress within Ascraeus Mons.

Cavalerio reclined in a contoured couch, his arms and skull sheathed in cables and haptic implants that burrowed beneath his skin like silver worms. This arrangement of a physical connection was fast becoming obsolete, a means of command seen as archaic by some princeps of Mars. Many were already embracing full body immersion in an amniotic tank that allowed information to flow like liquid through a virtual world, but Cavalerio much preferred an actual connection with the engine he commanded.

He knew the gradual atrophy of his body meant that he would soon have no choice but to accept emplacement within such a tank, for he could not endure the pain and stress, both mental and physical, of too many more separations.

That day was not yet here, and Cavalerio pushed the thought from his mind as he concentrated on the mission at hand.

Linked with the Manifold, Cavalerio saw the world around him as though the mighty structure of Victorix Magna were his own flesh and blood. The barren, cratered landscape of Mars stretched out all around him, the pale, ashen wastelands of the pallidus to the southwest and the tumbled rockfaces of the twin craters upon which Maximal's forge hunched like a collection of blistered towers.

Ahead, the tumbled, haphazard sprawl of the Gigas Sulci sub-hives filled the landscape, a wretched, sweltering collection of towers, habs and shanties that housed the millions of workers who toiled in the Fabricator General's manufactorum upon the towering, lightning-wracked slopes of Olympus Mons.

For days Kelbor-Hal's domain had been wreathed in seething thunderheads, the slopes and forges hammered by crackling bolts of purple lightning. Cavalerio didn't know what manner of experimental work the Fabricator General had going on, but it was creating some lousy atmospherics and interfering with vox-traffic for thousands of kilometres in all directions.

Every channel was alive with scrappy blurts of code that sounded like a chorus of urgent voices crowded into a single frequency. Cavalerio had been forced to mute the volume on the vox, the chattering nonsense code giving him a splitting headache.

Cavalerio put the Fabricator General from his mind and cast his augmented gaze far to the south, where thick clouds from the refinery fields of the Daedalia Planum smothered the landscape, smudging the horizon in permanent crepuscular gloom.

The three cobalt blue engines in Cavalerio's battle group marched at a steady pace along the borders between the territory of the Fabricator General and that of Ipluvien Maximal, striding like three great giants of legend.

On Cavalerio's left was the stately Warlord, Tharsis Hastatus, commanded by his comrade-in-arms, Princeps Suzak. Hastatus was a killing engine and Suzak a man who could be depended upon to deliver a lethal strike when it was needed most.

To his right, the Reaver Arcadia Fortis marched with eager steps, pulling slightly ahead of the main group. Its princeps, Ian Mordant, was a fiery-hearted hunter, a warrior recently promoted from a Warhound princepture who hadn't yet shed his preference for lone wolf operations.

'Close it up, Mordant,' said Cavalerio. 'My sensori tells me the ground here is soft and that some of the sand has shifted over the chasms. I don't want to have to call out a bulk lifter crew to lift your engine off its arse.'

'Understood,' came the terse reply, screeches and howls of interference scratching over Mordant's voice. Mordant was still getting used to the quirks of his new command, he and his engine still gauging the measure of the other, and his responses were typically brusque. Cavalerio only tolerated such behaviour because Mordant was one of his best warriors, with a kill tally only exceeded by his own.

'Still thinks he's a Warhound driver, eh?' said Kuyper, the Magna's moderati.

'Indeed,' agreed Cavalerio. 'The Arcadia will soon cure him of that, she's a stern mistress that's for sure. Any word from Basek?'

'Nothing yet, my princeps,' said Kuyper, consulting the vox-log.

'Sensori, do you have a fix on Vulpus Rex?'

'I think so, my princeps,' answered Palus, 'but these damned atmospherics are making it hard to keep a fix on their return. And our old girl's vision's not what it used to be.'

'That's not good enough, Palus,' cautioned Cavalerio. 'Find her. Now.'

'Yes, my princeps,' answered Palus.

Cavalerio gave his sensori a few moments before asking, 'Do you have her now?'

'She's further south,' answered Palus with a measure of relief, 'skulking around the edge of the Gigas sub-hives at the end of the Barium Highway.'

'Good ambush site,' noted Kuyper. 'If anything's going to come up on us, it'll be from there.'

'And they'll find Basek waiting for them,' added Lacus the steersman with relish.

Cavalerio nodded. Princeps Basek commanded Vulpus Rex, the finest Warhound Titan of Legio Tempestus, a fleet killer of engines far larger than its hunched feral size would suggest.

Pulling up the schematics of the surrounding landscape from the Manifold and meshing them with the topographical view afforded him through the Titan's senses, Cavalerio saw that Kuyper's assessment was correct. Only the Barium Highway was wide enough to allow an engine to pass without demolishing half the dwellings.

The confused tangles of glowing outlines that depicted the edges of the sub-hives were, however, outdated and likely to be inaccurate, so it never paid to be complacent where the safety of an engine was concerned. So much was built or demolished that most maps of the sub-hives were rendered obsolete on a daily basis.

'Bring us about on a heading of two-two-five,' ordered Cavalerio, feeling his muscles twitch as the mighty form of Victorix Magna swung about and began a stately march along the edge of Maximal's domain. 'Magos Argyre, what's our reactor status?'

'Assessment: borderline,' said Argyre, the Titan's enginseer, who stood immobile in his rear-mounted compartment behind the princeps's dais. 'We should not have marched, Princeps Cavalerio. The reactor's spirit is troubled and it is dangerous to walk without having recited the full litany of calming prayers to soothe its troubled heart.'

'So noted, Magos,' said Cavalerio. 'Bring us to slow march speed.'

'Slow march speed,' repeated Argyre.

Cavalerio monitored their surroundings through the depths of the Manifold, drinking in data from pressure sensors, atmospheric samplers, infrared panels and microwave receptors. His understanding of the world around him was unparalleled, his awareness unmatched by any other entity on the plains of Mars.

He tried to keep his attention focused on the ground before him, for the landscape around Maximal's forge was treacherous, but he found his attention continually drawn to the ugly, bruised skies above Olympus Mons.

'What are you up to, Kelbor-Hal?' he muttered.

'My princeps?' asked Kuyper.

'Hmmm? Oh, nothing, I was just wondering out loud,' replied Cavalerio.

Kuyper had caught his interest in Olympus Mons, their communal link to the Manifold allowing no secrets to exist between them.