He slammed a fresh clip into his bolt pistol. Squad Antiocles were being pushed back. The Devastators walked their fire closer in to the combat. A heavy bolter blasted half a dozen daemons into stinking meat. A missile blew, lifting more into the air. Messinius fell back himself now, leaving it to the last moment before ordering the Assault Marines to leap from the fray. Their jets ignited, driving back the daemons with washes of flame, and they lifted up over his head, leaving four of their brothers dead on the ground. Devastator fire hammered down from above. Anti-personnel weapons set into casemates and swivel turrets on the walls joined in, but the daemons mounted higher and higher in a wave of red that flooded over the parapet.

‘Run!’ he shouted at the straggling human soldiery. ‘Run and survive! Your service is not yet done!’

The Penitent’s Arch led from the square onto a wall walk that curved around to another layer of defences. His Space Marines were already making a firing line across the entrance. A gate could be extended across the arch, sealing the walk from the square, but Messinius refrained from requesting it be closed, as the humans were still streaming past the Adeptus Astartes. Kryvesh waved the banner, whirling it through the air to attract the terrified mortals. The Space Marines fired constantly into the mass of daemons sprinting after them, exhausting their ammunition supplies. Shattered false bodies tumbled down, shot from the front and above, yet still they came, overtaking and dismembering the last warriors fleeing away from the parapet.

Squad Antiocles roared through the arch, landing behind their brethren. Messinius passed between them. For a moment he surveyed the tide of coming fury. Endless red-skinned monsters filling the square like a lake of spilled blood, washing over a score of brightly armoured Space Marine corpses left behind in the retreat. Several hundred humans lay alongside them.

He opened a vox-channel to Gate Command.

‘Wall batteries three-seven-three through three-seven-six, target sector nine five eighty-three, Penitent’s Square, western edge. Five-minute bombardment.’

‘On whose order?’

‘Captain Vitrian Messinius, White Consuls Chapter, Tenth Company. I have the primarch’s authority.’ As he dealt with gunnery control, he was also datapulsing a request for ­resupply, and checking through layered data screeds.

‘Voice print and signum ident match. Transponder codes valid. We obey.’

The far side of the square erupted in a wall of flame. Heavy ­cannon shells detonated in a string along the rampart. High-energy beams sliced into the square, turning stone and metal instantly to superheated gas. The approaching daemons were annihilated. A few bolt-rounds cracked off as the last daemons nearing the Space Marine line were put down.

‘Company, cease fire. Conserve ammunition.’ Nobody heard him. Nobody could. He re-sent the order via vox-script. The boltguns cut out.