For more than one hundred hours, the battle raged. Then the manu­factorum cried out. A mountain chain of infernal creation screamed with a throat of stone. Fissures snaked up the heights of the walls. Chimneys three miles high wavered. Their bases crumbled, and they dropped like broken spines into the pyres of chaotic lightning. The fissures widened. Howling light burst from them. The warp lightning punched holes through the towering doors. The daemons in the field moaned as one, and abandoned the attack. Their reduced army melted away, flowing back into the secondary foundries. Soon the high towers on both sides of the battleground began to flash. Streaks of corrupted light shot upwards to the base of the fortress.

‘They flee,’ the Lion voxed.

Guilliman turned to the primary foundry’s doors. They were still closed. ‘Brother,’ he called to Sanguinius. ‘Can you hear me?’

There was no answer at first. It wasn’t long, though, before one came. When a huge split appeared the entire height of the doors, Sanguinius’ voice reached Guilliman. ‘We are coming out, Roboute. We have done what we came to do.’

‘I can see that.’ The manufactorum was a volcano about to be blown apart by its internal forces.

‘Can you clear the terrain for the Stormbirds to land?’

‘That will not be a concern. They have quit the field. Focus your efforts on escaping the site of your triumph. Don’t let it be your tomb, Sanguinius.’

‘It won’t be.’

Guilliman was struck by the ringing confidence in Sanguinius’ voice. He had become used to hearing his brother’s iron fatalism. Sanguinius sounded different now. For the first time since they had been ­reunited on Macragge, Guilliman heard the Angel speak with real hope.

The manufactorum convulsed. A series of explosions mounted the pillar joining it to the keep’s gate. They began as pinpricks on the umbilical length, then became a pulsing river of fire. A blast at the base of the fortress gate was larger than Pyrrhan itself. The terrain before the manufactorum shook with constant tremors. A widening web of fissures extended from the foundations. To the south, for as far as Guilliman could see, clouds of dust erupted as the ground cracked.

‘Withdraw, brothers,’ Sanguinius voxed to Guilliman and the Lion. ‘This battle is finished, and greater victories will come.’

‘You saw something in there, Sanguinius,’ said the Lion. He sounded almost accusatory.

‘I did,’ said the Angel. ‘I saw hope. We are not slaves to fate, brothers.’