What intrigued Felix was how the primarch explained his actions. Whichever he said was most important to him depended on who he was speaking to. In this way, the primarch directed the energies of his followers according to their own prejudices without actually lying to them. There were almost certainly other factors he kept to himself. This level of layered communication astounded Felix. Though he understood it well enough, he felt he was seeing something that had been in front of his nose for years. Guilliman often spoke of the Adeptus Astartes’ capacity for peaceful as well as martial endeavour. Felix thought he overestimated their capabilities. Grappling with the concepts of administration made him feel apish in mind, as if his brain were not truly made for it, even though the primarch assured him he was talented in that direction.

Maybe it was a matter of training. He had spent thousands of years preparing for war, and only five practising statesmanship. If the primarch said so, then it must be true. Even so, Felix had so much to learn. He was bewildered by the facility with which the primarch got people to do what he needed them to do almost without effort. If he could emulate only a tenth of what Guilliman did, then he could count himself worthy of being a tetrarch.

Felix dearly wanted to be the one to find the fallen primarch’s machine, and help deliver it to the Avenging Son. Destroying the Ardium clock had been child’s play compared to tracking this one down. Stopping its infernal workings would be an achievement he could understand. Then he might feel worthy of the honour bestowed upon him.

The assault was faltering. All across the front the Space Marines were slowing, caught by the sticky embrace of the ground. They had begun their run from the Imperial trench line gleaming, all their colours bright and clean. Now they were caked in filth, a uniform grey-brown. The mud was an unspeakable slurry, as much corpse flesh as soil and water. It came up to Felix’s breathing grille. His armour sealed itself against the mess. A chime warned him that his thermal vents were closed, drawing his attention to a pair of bars among a miniaturised display of many indicators. The relevant measure magnified itself, blinking urgently. Slowly but surely, the temperature rose. His reactor pack became noticeably warm. All his indicators for the battleplate’s fibre-bundle stressing were creeping out of their green segments into amber.

When the charge was mired in the river, the Death Guard opened fire upon the Space Marines. They had no choice but to endure it. Guilliman had sent the Space Marines forwards because mortal men could not breach the sea of mud. Now they must trust to their armour.