Gerrundium nodded. ‘Disease alone cannot bring back the fallen, nor turn those who live into walking corpses.’ He sounded flat and passionless, his own coping mechanism against the corruption they neared. ‘That is a physical impossibility, as our Apothecaries and the primarch’s magi attest. Sorcery is the root of the disease. Without the warp, there would be no consequence to infection.’

‘The plague lord delights in the affectation of disease where disease alone is insufficient for his goals,’ said Maxim. ‘Lies are as great a part of their armoury as contradiction. They are the basis of the actions of the enemy. Nurgle represents the duality of life in death and death in life. As with all things of the warp, it is unclean and a trap for the unwary.’

‘You include your own abilities.’

The Codicier grunted. His helmet turned within his protective aegis helm. ‘Our gifts bring great power, but they spring from the same poisoned well as diseases that rot the soul. To drink from it and remain pure is the greatest challenge we face.’

‘We feel this strongly because there is a wicked power at work. It is from the Palace Spire that the corruption emanates,’ added Gerrundium, ‘but we will not know its true nature for certain until we witness it ourselves.’

The Overlord shook. Its armour was massively thick, and its engines prodigiously powerful. The new craft made Thunderhawks look like toys. As with so much the primarch had commissioned, the Overlord hearkened back to older designs of insertion craft, improved by the boundless creativity of Belisarius Cawl. But its technological power could not shelter its occupants completely from threats either mundane or arcane. The movement of the craft changed; no longer was it affected solely by atmospheric anomalies. An explosion sounded close by, its violence muffled by the Overlord’s thick hull. The craft slid sideways before levelling out. Smaller vibrations, rapidly pulsed, chased it upwards.

‘Captain, there is unexpectedly heavy fire coming from the Palace Spire’s mid ranges,’ voxed the pilot. ‘We cannot land at the target point.’

‘Get us as close as you can,’ responded Felix.

‘There is a skypark cluster four hundred metres horizontal, two levels down from the target point and in the next spire.’ The pilot went silent a moment as he consulteda cartograph. ‘The Sighing Spire.’

The pilot exloaded the position. Felix’s cartograph automatically engaged. They headed for a cluster of spire palaces at the very pinnacle of one of Ardium’s great hive cities, their needle points pricking at the belly of the void. Felix saw them as wireframe representations. Ugly, semi-organic growths moved sluggishly over the top, a psychic overlay provided by the primarch’s Concillia Psykana. The shifting web gathered most densely on a cankerous mass in the upper reaches of the tallest tower, once the home of the hive lord.