Theoretical, he thought. The Emperor is a god and denied His own divinity to protect humanity. Practical, He is a god.

Or, he continued to himself, Theoretical, the Emperor was not a god, but became one. Practical, He is a god.

He dismissed the idea angrily. These theoreticals had trooped through his thoughts so many times before he had grown weary of them, but his mind would not stop generating counter-arguments to his beliefs.

Theoretical, the Emperor was always a god, but was unaware of it. Practical, He is a god.

No, he thought.

Theoretical, the Emperor became a god to protect humanity. Practical, He is a god.

He is not a god, he thought.

Theoretical, Guilliman thought savagely now, turning his anger against his traitorous mind. The Emperor was never a god, denied He was a god and has been wrongly elevated by men who see power and mistake it for divinity. Practical, the Emperor is not a god.

‘He is not a god,’ said Guilliman out loud. He could not countenance the thought. A being that cold and callous was not worthy of worship.

Why, then, did the question dog him so?

‘My lord?’ asked Maxim. ‘Are you well?’

‘It is nothing,’ said Guilliman, coming to his senses. He looked towards the end of the cathedral where darkness held its secrets close. ‘I do not see anything, though the atmosphere suggests all is not well. Where is Mortarion’s device?’

‘The device is here. It will be at the high altar,’ said Tigurius, pointing to the uncertain gloom filling the cathedral’s exedra. ‘It hides itself from us in a cloak of bound shadow.’

‘There is something there,’ said Maxim. ‘I can feel it.’

Guilliman looked down the cathedral’s long aisle. A kilometre of polished marble floor heaped with broken roof tiles were between his party and the exedra housing the altar. His armoured fist flicked a quick signal to the Sisters of Silence in battlemark, their simplified combat language. They bowed and moved quickly up the aisle. True to their name, they made no sound as they advanced, their armour silent and their feet noiseless on the wreckage of the church. Their silver plate vanished into the gloom holding the far transept to ransom.

‘Let them go ahead first,’ said Guilliman. ‘If there is illusion here, their unique gifts will tear it away.’

They waited a while. The darkness did not lift, until a pulsed vox click came into the primarch’s helm. The shadows remained thick, hiding their secrets, the Sisters shrouded now also.

‘They have found it,’ said Guilliman. ‘Come.’

Guilliman’s progress up the aisle was far less stealthy than the Sisters’. The shattering of roof tiles under his feet echoed loudly around the ruined cathedral. Twenty Librarians of half a dozen Chapters marched in solemn ranks behind him.