‘Before we came here, I had Tetrarch Felix lead an expedition to the Palace Spire of Hive Creostos on Ardium,’ said Guilliman. ‘I needed to know how my brother is effecting this plague of the dead, and how his daemonic allies are able to cage themselves in false flesh so easily in the heart of our kingdom.’ He paused. ‘There are certain writings that refer to an artefact known as the Hand of Darkness. I believed this device to be the cause.’

‘We know of it,’ said Calgar. ‘It was taken by Abaddon centuries ago, and used by him in the Gothic War. Some learned men say it allowed him to subvert the Blackstone Fortresses in the Gothic Sector. There is little else in our records.’

‘It is an ancient device, from aeons before the first age of humanity in the stars,’ said Guilliman. ‘He who possesses it can direct the energies of the warp easily, and on a massive scale.’ He paused again. ‘It has come to my knowledge that Mortarion has it – a gift from the Despoiler.’

‘From which source do you know this?’ asked Calgar.

‘The Ynnari of the aeldari. They did not claim the device as theirs, but I suspect it was crafted by their forebears. They have an interest in knowing its whereabouts.’

A murmur passed through the crowd. The aeldari had been instrumental in returning Roboute Guilliman to life, but they were xenos, and could not be trusted.

‘Peace, my people. I do not take their word at face value. It was one of many things their envoys revealed to me during my journey to Terra. They insisted that the dead walked at Abaddon’s command across the galaxy because of some subversion of this device by Mortarion. When tidings of this new plague of the unliving afflicting Ultramar reached me upon my crusade, it gave weight to their argument. The rebellions we have been suffering added to my conviction. They are a madness, and what is madness but a malady of the mind? Observe. Sisters, activate the hololith.’

One of the Sisters of Silence turned the device on. It thrummed powerfully. Loop projectors glowed as the emitter set up a limited-composition stream-projection cone that glowed silver and white.

‘The Sisters stand guard around this thing to shield you from its power,’ said Guilliman. ‘Even an image of it has the potential to corrupt.’

Combat feed taken by Felix’s helm lenses took shape on the hololith, displaying the strange clock from the Palace Spire chapel.

‘Now see,’ said Guilliman. At a pass of his hand, a further layer was added to the image, a web of globular strands that overlaid one another and pulsed menacingly. They were such a dark green that they were almost black.

‘That does not look like how I imagined the Hand of Darkness,’ said Calgar. ‘I say that is not it.’