The chamber was hot, loud with the chatter of hidden machinery and heavy with a sense of foreboding. Once through the doors on the far side of the chamber, that sensation would grow worse as Guilliman was exposed to the psychic circuitry of Cawl’s blasphemous device. First he must undergo another series of tests. Again, he passed each one, and the chamber’s far doors opened into a second and much larger circular space, lit the same bloody colour. The doors were complex, three interleaving sets of metre-thick bonded hexsteel whose toothed edges clunked ominously as they unlocked from each other. The chamber’s spherical exterior walls were similarly armoured. Cawl’s machine would survive the death of the Macragge’s Honour itself.

Guilliman readied himself for the greater psychic pressure and stepped inside.

His head throbbed. The air smelt of ozone, sanctified oil, curdled milk and old blood.

At twenty metres across, the interior space of the machine was modest by voidship standards. A grilled floor was suspended over a pit full of humming machines, dividing the interior space into two. Quieter than virtually everything Guilliman had seen in this benighted era, the machines nevertheless made the room vibrate at a high frequency with the turning of their parts. Through the floor grille came the majority of the red light, confusing shadow and highlight and breaking down any visual sense of the space.

‘Lumens!’ barked Guilliman.

The machinery’s high whine dropping to a grumble. The red crept down the walls, like fire dying. The metal of the room groaned in relief, as if the touch of the red light had a physical effect upon it. Hard-white lumens snapped on above, banishing the sanguine glow to beneath the flooring and bringing the room’s features into sharp focus.

The chamber seemed smaller in the cleaner light, and its features were clearly resolved. A small door opened directly opposite the main gate. Closed panels at a man’s eye level lined the walls between the two doors, ten on the left and ten on the right. Pipes bound tightly by metal staples hung in swags from the ceiling. A small mercy, in Guilliman’s opinion, was that the chamber was free of the gothic extravagance that encrusted everything else in the 41st millennium. It was pure of form, if not of function. The Machina Opus glaring down from a rondel set into the domed ceiling was the sole decoration; even Belisarius Cawl was not radical enough to omit that symbol.

The room’s other access slid upwards. It, too, comprised three massively thick doors that opened in sequence. On the far side were the quarters of Guidus Losenti. They were totally black, for Losenti had no need of light of any kind.