Thus it was that – with breath-taking efficiency – huge numbers of Ultramarian casualties were broken down by stages into the smallest manage­able groups. Hundreds of thousands of men became thousands, then hundreds, then tens. And all were thoroughly, relentlessly catalogued by the Officio Medicae’s Divisio Descriptor. Elsewhere in the Imperium, such work would have been unimaginable. On most worlds it would never have been undertaken – the sick would have been exterminated; the wounded would have been left to their fate.

Not in Ultramar. The white-and-blue-clad human auxiliaries each represented a significant investment in training, and most had accrued substantial combat experience. By treating and returning its casualties to the war, the realm of Ultramar kept its armies fighting without loss of expertise or effectiveness at the height of the Imperium’s darkest period.

‘By the preservation of life do we maintain our capability to mete out death.’ So the primarch had said. Or, at least, the records indicated he had said so. Now Guilliman was among the living once more, it was possible to ask him if all the words attributed to him were truly his. For the first thirty years, Guilliman had been in the habit of correcting his subordinates, insisting many of his supposed sayings were apocryphal, until he had given up in exasperation. He was simply not believed by most, for whom the primarch remained an ideal. They valued their preconceptions of him over the living evidence.

Despite this mass cognitive dissonance, no one could argue that the efforts to save the troops’ lives were undertaken in a manner at odds with the primarch’s own beliefs. Though diminished in efficacy, something of Guilliman’s meticulous methodology had survived the ages.

Iax had become the hub for all counter-plague efforts, a laboratorium and sanatorium both, where treatments for the war’s ever-evolving sicknesses were concocted and disseminated to the fronts of Ultramar’s war as fast as the enemy could unleash them.

The processing of casualties was labour intensive, no matter how efficient. Ensuring the purity of bulk landers was hard, so they were forbidden from the surface, but smaller lighters or shuttles meant more trips. As a result, landing all the troops from a single medicae ward-ship took a long time, and there were always plenty more waiting.

To the untrained eye, the cleansing of the landing aprons was an impressive sign of the diligence with which the screening procedures were undertaken. In reality, it was the least important and easiest, entrusted to low-ranking ground crew and mono-task servitors whose biologic components were sealed deep within inorganic frames.