With the deck shuddering beneath them, Varren and Garro sprinted the last few metres to a floating service platform hovering alongside. Garro, serving as the Sigillite’s Agentia Primus among the Knights-Errant, was commander of this mission, and he would have been within his rights to chastise Ison and Varren for almost getting themselves killed – but that wasn’t his way. The former Death Guard battle-captain and the Hero of the Eisenstein was unlike the warriors Varren had served under in the XII Legion – never quick to his rage, never leading by fury when reason could serve as well. It had taken him a while to get used to it, but in truth there would always be a part of Macer Varren that expected death to meet him. When his primarch and his Legion had broken faith with the Imperium, Varren’s refusal to follow had started the pendulum swinging on a clock that counted down his days.

Climbing aboard the sputtering, overloaded grav-platform, he spied Helig Gallor – another Knight-Errant from Garro’s old Legion – at the controls and threw him a nod. Did Garro, Ison and Gallor think of their time as Varren did of his? His lips parted in a feral grin. I’ll probably be dead before I ever have the chance to ask them.

‘Go!’ called Garro, and the platform shot forward, up and around the Walking City’s eastern quarter.

Varren shoved a few whimpering civilians out of his way so he could get a better look at the metropolis. He estimated over a third of the city was on fire, although it was hard to be sure if the black smoke he saw was from conflagration or if it was more of the gargantuan insect swarm. The moving construct had lost one leg on the western side, and it appeared to be stumbling forward on an uncontrolled course. Ahead of it, the walls of a steep-sided valley were narrowing.

‘Are we retreating?’ Varren asked to the air. He glanced at the handful of civilians. ‘This is a pitiful number to count as rescued.’

‘We are regrouping,’ Garro countered, as Gallor brought the grav-platform up and over the Walking City’s spinal boulevard. ‘Look there.’ Again, he pointed with his power sword, and Varren spied the target at once. A towering column of shimmering darkness that did not move as smoke did.

As he watched, the legionary saw the swarm thicken and solidify. ‘It’s taking on a shape…’

‘Billions of those carrion flies, merging together,’ said Ison. ‘I have an inkling of the enemy’s intention.’ He glanced at Garro. ‘You won’t like it.’

Varren felt a jolt of cold understanding. ‘It’s going to infest the city’s machinery, just like it bred inside the flyblown.’

‘The World Eater has it,’ agreed Ison.

Gallor frowned. ‘Can they do that?’