‘I’m not sure.’ He looked at the Avenging Son. ‘Can’t you feel it?’ The temple’s air had been stagnant and dead since the main gate. In the last few minutes, it had grown charged, as if building up to something.

‘I don’t feel anything,’ said Guilliman.

‘Nor do I,’ the Lion added.

Sanguinius wondered if he was wrong, if his conviction was manufacturing anticipation.

Curze was silent, his expression closed.

On a level directly up from the hidden room, under the dome, they found an altar. It was the first object they had seen. It was in the centre of a chamber so narrow it was more like a cylinder. The walls went up a hundred feet to the dome, but the floor was less than twenty feet across. The primarchs entered by the single doorway. Their legionaries waited in the larger hall outside. The altar was a single large slab, over ten feet long and five feet high. It was a much deeper red than the rest of the stone of the temple. It was almost black. There were stains on the surface too. Unlike the pattern in the chamber below, these appeared to be the pooling from a wound.

Sanguinius stopped on the east side of the altar with Curze. Guilliman and the Lion stood on the west. The gaze of all four alighted on the stain, and lingered.

‘He lay here,’ said the Lion.

Guilliman nodded.

Sanguinius said, ‘This is where his fate took shape.’ He struck the altar with the pommel of the Blade Encarmine. The ringing of metal against stone was loud and hollow. ‘Here,’ he said again. ‘The war began here.’ He wanted to say the war would end here too. He could not. Yet there was symmetry at work in the presence of four primarchs here. The journey from Macragge was a descent further and further into the very heart of the war.

They were there now, at the fulcrum of space on which the galaxy had turned and fallen into flame.

The air should have trembled with the import of this moment. Instead, there was nothing. The event Sanguinius anticipated did not arrive. He considered the possibility of self-delusion, and discarded it. This was where he and his brothers were meant to be.

And yet.

Stale air hung in the chamber. The altar was covered by the layers of the past.