The Battle of Constanix II

The Heresy did not spare the priesthood of Mars; it split the Machine God's servants as surely as it split the Legions. The Battle of Constanix II was one of the ugliest wounds of that schism, a war for a forge-moon where the Mechanicum turned its own boundless industry against itself, foundry against foundry, cohort against cohort, in a fratricide of iron and sacred oil.

Above and among the manufactorum-spires strode the god-engines of the Legio Titanicus, and here the true horror of the age revealed itself, for these were not enemy machines but brother-engines, Titans that had marched side by side in the Great Crusade now duelling to the death across the moon's blackened plains. Void shields flared and failed, reactors bloomed into false suns, and princeps who had once shared the Manifold now hunted one another through the ruins with cold, deliberate hatred.

Neither side could easily claim Constanix II, for its worth was too great and its defenders too fanatical. The forge-moon became a grinding wound in the side of both causes, its production strangled, its adepts martyred by the thousand. When at last the guns cooled, the moon was a scarred monument to a truth the Mechanicum could never again deny: that the Machine God's children had learned to hate, and would tear their own temples down to prove it.