The barrier was narrow, just as Pyriel had warned, and as the Phalanx had tried to keep pace with the Salamanders on the way to the advanced assault line some stepped out of it. A muted cry and then they were no longer seen or heard from again. By the time the firing line was erected, some several dozen troopers were missing. The Salamanders, as yet, had not succumbed.

Tsu’gan saw the flickering white forms of the warp echoes through the Librarian’s psychic shield. They lingered, angry and frustrated, ever probing to test the limits of Pyriel’s strength. Though he couldn’t see his face through his battle-helm, Tsu’gan knew by the Epistolary’s juddering movements that he was feeling the strain. He was a vessel now for the near-unfettered power of the warp. Like a sluice gate let free, the energy coursed through him as Pyriel fought hard to channel it into the shield. One slip and he would be lost. Then Tsu’gan would need to act quickly, slaying him before Pyriel’s flesh was obtained by another, heralding the death of them all, Salamanders or no.

One of the creatures breached the barrier wall, corporealising to do it, and Tsu’gan lashed out with his fist.

It was like striking adamantium, and he felt the shock of the blow all the way up his arm and into his shoulder, but did enough to force the creature back. It flashed briefly out of existence, but returned quickly, a snarl upon its eldritch features.

‘Hard as iron you said,’ Tsu’gan roared into the comm-feed as the weapons fire intensified.

Overhead the Earthshaker shells were finding their marks and the void shield rippled near its summit.

Emek battered another of the spectres back beyond the psychic cordon, the exertion needed to do it evident in his body language.

‘Perhaps too conservative,’ he admitted.

‘A tad, brother,’ came Tsu’gan’s bitter rejoinder. ‘Iagon,’ he relayed through his battle-helm, ‘what are the readings for the shield?’

‘Weakening, my lord,’ was Iagon’s sibilant reply, ‘but still insufficient for a break.’

Tsu’gan scowled.

‘Ba’ken…’

‘We must advance,’ the acting sergeant answered. ‘Fifty metres, and apply greater pressure to the shield.’

At a hundred and fifty metres away, the danger from energy flares cast by void impacts and friendly fire casualties from the Earthshakers was greatly increased, but then the Salamanders had little choice. Soon the bombardment from the Basilisks would end when they ran out of shells. The void shield had to be down before then.

‘Brother-Librarian,’ Tsu’gan began, ‘another fifty metres?’

After a few moments, Pyriel nodded weakly and started to move forwards.

Tsu’gan turned his attention to the Phalanx.

‘Captain Mannheim, we are advancing. Another fifty metres.’

The Phalanx officer gave a clipped affirmative before continuing to galvanise his men and reminding them of their duty to the Emperor.

Despite himself, the Salamander found he admired the captain for that.

The bells tolled on as the Imperial forces resumed their march.

The stairs were shallow and several times Dak’ir almost lost his footing, only narrowly avoiding a plunge into uncertain darkness by bracing himself against the flanking walls.