‘You are correct, Lord Calgar,’ said Guilliman. He was distracted, somewhat distant, in his troubled state he unknowingly spoke down to the Lord of Macragge. ‘It is not the Hand of Darkness itself, but a device created by Mortarion using the hand’s power and knowledge he has prised from its workings. This network you see here is psychic in nature. It spreads all over Ardium and beyond, reaching from world to world where similar devices are located, aiding the armies of the Plague God. Codicier Maxim, please.’ Guilliman gestured to the Chapter Aurora psyker.

Maxim rose from his position among the assembled Space Marine leaders. He had come to the meeting bareheaded. Beneath the deep blue of his armoured cowl was an old man who had seen enough evil to last several lifetimes. His snowy hair played host to cables burrowed into his scalp. Power shone in the whites of his eyes. They were caged by wrinkled skin, topped by a brow caught in the collapse of a frown that would never lift.

‘I have felt this… uncleanness too closely,’ said Maxim. ‘The touch of it pollutes my mind still. This machine dirtied the psychosphere of Ardium like sepsis in blood. Mortarion has created a psychic weapon that has our people turn against their rulers in the face of all sense, and the dead turn against the living. A net of corruption has been hung about Ultramar by the fallen primarch. Mortarion draws it ever tighter. He sickens the realm in the same way he infects a single man with his phages.’

‘Lord Tigurius had sensed something of this,’ said Calgar. ‘We had no idea of the scale of it.’

‘You did not,’ said Guilliman neutrally. ‘Mortarion’s Legion was famed for its commitment to blunt assault and an obsession with staying power in the face of overwhelming enemy fire. They were crude strategies born of pride, and costly. But he is capable of subtlety, and when he chooses the quiet game he is at his most dangerous.’

‘It would explain why his movements have appeared so random,’ said Captain Torkos of the Howling Griffins. ‘If he were planting these devices…’

‘Quite,’ said Guilliman. ‘My once-brother made these things. He is installing them himself. He never did trust others. Consider how your defences have failed in the areas Mortarion has been seen. The capabilities the devices grant him concern me. If he can draw so directly upon the empyrean in so many locales, other options might be open to him in addition to the creation of undead hordes and the poisoning of minds. The Cicatrix Maledictum’s influence should be weak here in Ultramar, but I find it is not. Mortarion is the cause. The aid of his diseased master is always close to his hand. What is occurring on Iax, for example, gives me great cause for worry. The daemons were brought there, somehow, through this warp network derived from the Hand of Darkness.’