They were not Legion ships either. These were ships of the Mechanicum, each one a relic and expression of their master’s power and knowledge. All of them were disciples of the new path of the Machine Cult. Somehow, this new creed had spread far beyond Mars, beyond the Solar System. It had infected forge worlds and tech-fanes and remade those that embraced it into something new and terrible. The things that they made were not mysteries or wonders; they were abominations. Machines that broke reality, and creatures that were neither flesh nor machine yet lived – all these things came from their craft. Time and simple sentiment had given them a name that followed them across the stars and clung to the shadow of their passing. The Dark Mechanicum they were named, and now they had returned to claim the seat of their empire.

The first shot was theirs. Fired from beyond the range of Camba Diaz’s weapons. A beam of cold light a hundred metres wide bored down through the dark. The ships in its path tried to move, but the beam twitched and coiled through the void like a snake. It struck the cruiser First Truth. The energy flowed over its void shields and hull like water around a stone. On board, its crew had seconds to watch as their system readouts spiked. Then the flow of energy sank through the void shields and into the ship’s hull. Every system and machine cut out. Light vanished. Engines died.

There was a moment of silence filled with the breaths of the crew. Then every machine on the First Truth screamed. Cogitators melted. Power governors exploded. Vox-processors howled static. The ship came apart, components scattering out as gravitic generators reversed. Layers of metal and stone peeled back until its reactors spun free, arcing with power, an exposed heart still beating in an opened chest. Then the reactors overloaded and a wave of burning light tore through the broken hull.

The beam snapped across the void, seeking another victim even as ships burned thrusters to move out of its way.

The Fourth Sphere fleet began to loose torpedoes and maximum-range shots at the oncoming Dark Mechanicum. The guns of all their ships spoke and the space between the two fleets became a blaze.

Rockets and beams of energy rose from Mars towards the ships in close orbit. Its thin atmosphere flashed and shivered. Craft built in the forges of the fallen magi rose from caverns hidden under the Red Planet’s crust. They were things from the fever dreams of tortured machines. Wings of brass feathers spread from under cases of steel and black glass. Tails and necks uncoiled from fuselages, and multicoloured flame roared from engines.