Machines hidden behind the panelling surged into life. The chug of the devices below them grew more muted, ceding space to the waking voices of the others. Thin lines in the metal walls, invisible before, glowed with sluggish, golden energies. Circuitry engraved into the tanks’ glass glimmered similarly, and the faces of the heads twitched. Guilliman was absorbed by the jerking of their muscles. The weight pressing onto his psyche grew.

Losenti grimaced at the primarch. ‘I ask your leave to depart, primarch,’ he said. ‘The awakened machine’s presence is uncomfortable for me.’

‘Yes, yes, of course,’ said Guilliman. He tore his eyes away from the severed heads. ‘Please. You do not need to ask my permission. We have done this many times. I know how much the Cawl Inferior pains you when active.’

Losenti gave a slight, grateful bow, tugged up his hood and walked back towards his perpetually dark quarters.

‘Losenti!’ called Guilliman on a whim, raising his voice over the smooth thumping of the machine. Losenti paused at the threshold of his door. ‘What do you do down here, when you are not needed, when you are alone?’

Losenti turned his head. His wrinkled face was bathed in the warm light of Cawl’s device. ‘I write poetry,’ he said. ‘And I dream of better times.’

The doors slid shut behind him, leaving Guilliman alone in the chamber of the Cawl Inferior.

Guilliman lacked the psychic potential that His father had granted to several of his brothers, but he was a child of the Emperor’s making, and he was sensitive to psychic energies of which a true non-psyker would be ignorant. Some hidden part of the world changed. Energy ran more freely around the channels engraved into the walls, extending its web outwards from the heads until the whole room was a tracery of golden lambency. The yellow light outshone the ruddy light of the machine hall under the floor and the bright lumens overhead. As the energy network expanded, it hit upon hidden signs in the fabric of the room. Warding runes in the secret techno-arcana tongue of Magos Psykana blazed brightly, along with others of obvious alien origin. Cawl was a magpie magos, taking what he needed no matter its ancestry. His free thinking made Guilliman profoundly uneasy, but a labour ten thousand years long, delivered perfectly, attested to the archmagos’ efficacy. He had been instrumental in restoring Guilliman to life in this terrible age. And, most amazingly, in creating the Primaris Space Marines, Cawl had improved upon the Emperor’s own designs.

I have no choice but to trust him, thought Guilliman. That’s the only practical I need consider here.