The total efforts of star systems went into the construction of these fleets. Neither was free of the taint of blood, not in their construction – for tens of thousands of lives had been expended in their making – nor in their usage. The resources of planets had been poured entire into the forging of their frames, and the secrets of ancient sciences plundered to bring them to murderous life. Both had been responsible for the levelling of civilisations.

The fleets differed in only two regards. First was in their appearance. One was a gaudy assault on the senses, the other a motley collection of sober liveries. The second and more fundamental difference was in their allegiance. The sober fleet fought for the continuation of humanity’s great stellar empire; the gaudy one was dedicated to its extinction.

The battlefleets pursued each other in a slow dance that broke through Thessala’s rings, hundreds of vessels ploughing gaps through the dust that would take centuries to close. The voiceless lightning of their guns filled the skies of Thessala’s inhabited moons. The lives of millions below depended on the outcome of the battle, but the consequences would ripple much further.

At the centre of this iron storm there was no calm, no eye in which respite might be found. Instead, there was a pair of leviathans: the Ultramarines battle-barge Gauntlet of Power and the Emperor’s Children battleship Pride of the Emperor. Two vessels, forged in a common cause but now implacable enemies, locked together in mortal combat only thirty kilometres apart – no distance at all in void war.

Each was the flagship of a primarch, genetically engineered demigods crafted by the Emperor of Mankind. Aboard the Gauntlet of Power stood Roboute Guilliman, the foundling of Ultramar, the Avenging Son. The Pride of the Emperor was home to Fulgrim – the traitor, the fallen exemplar, the blighted phoenix. Once covered in his Emperor’s blessings, Fulgrim had followed the arch-traitor Horus and pledged his allegiance to ancient dark gods, becoming the herald of perversity.

In fighting for their father, both primarchs were made fathers themselves, though not of princes or strong daughters; through the application of arcane science, they were the sires of two of the Space Marine Legions, mankind’s greatest warriors. The Space Marines were lords of the galaxy, designed to reunite the human race and shepherd it to a glorious future. Instead, they had failed and turned upon one another, and their war had nearly destroyed the Imperium.

Such fury a battlefleet can unleash!

It can cow a world without a shot. It can extinguish the life of a species. Battlefleets are the tools of tyrants, whomever they fight for. Whether their admirals espouse salvation or damnation matters not to the execution of their purpose. Death follows in their wake.