He prepared to die. Abruptly, the pressure ceased. The Mechanicum troops stood back, stood to attention and put their weapons at rest. Bror leapt up. He tore the head off one of the cyborgs before he realised they had stopped fighting and become as motionless as model soldiers.

He turned around. Gren had joined Flokr in death. Himmlik was slumped against the wall, his bloody hands clutched over the shattered armour covering his stomach. Fires guttered in craters in the walls. A ruptured pipe jetted thick clouds of chilled carbon dioxide into the corridor past the Wolves. The glowing red eyes of Mechanicum cyborgs shone in the artificial mist, but they did not attack.

'By the third head of Morkai! What is happening?' said Enrir.

Bror pulled off his helmet and gulped down air thick with the stench of death and lubricant.

'More twists in the wyrd,' he panted.

A lone figure advanced down the corridor towards them through the battle smoke.

Ragner took aim.

'Do not shoot!' commanded Bror.

'I come to you in truce,' said the warrior in a flat, machine voice. He came closer, stepping out of the swirling gases. 'You are not a valid target,' he said. His crest and the insignia on his grey-and-red coat marked him out as a skitarii clade alpha.

'Then why did you attack us?' said Bror.

'Direct oversight from subverted command centres. You are not a valid target,' repeated the warrior robotically. 'You are Space Wolves, Legiones Astartes Six. Loyal to the Emperor. You are not a valid target.'

'Do you know where you are?' asked Enrir.

'I do not,' said the skitarii.

'You are aboard the Vengeful Spirit,' said Enrir. 'You were fighting for the Warmaster.'

The warrior fell silent. Tiny dicks and whirs sounded in his skull. 'Then our leader was in error. We were set against you without consent of this forge world's master. The moment of communion with the Motive Force is over. We have been reset to self-determination parameters.'

'Who is in command now?' asked Ragner.

The warrior was silent. The remainder of the pack tightened their grip on their weapons.

'I am,' the skitarii said.

'Then are you for or against the Emperor?' asked Enrir.

Again, that long silence.

'The Emperor is the rightful ruler of the Imperium. Kelbor-Hal is a traitor to the species. I am a loyal servant of the Imperium of Terra and Mars. I will fight with you.'

'What's your name?' asked Enrir.

'My designation is 978-1849700764.' He made the sign of the cog over where his heart had once been.

'That's your name?' said Enrir.

'That is my designation,' said the warrior. 'My name is Diort.'

'Diort,' said Bror.