Dozens of urns in the lower levels of the Ossuary shattered, spreading the bones of former castellans across the floor. Skulls grinned up at Cycerin as he passed, making his way to the Sepulchre's exit.

At the door to the outer chambers, he stopped, lowered his arms and waited.

Jharek Kelmaur picked his way painfully down the rocky slopes, pleased that he had answered the potential of his vision. He did not know what part Adept Cycerin had yet to play in the unfolding drama on Hydra Cordatus, but was satisfied that he had been instrumental in its fulfilment.

As soon as Cycerin had vanished, the pattern etched in the bronze disc in the floor had begun to fade along with the glow in the walls, until any hint that either had existed was gone. The scroll had crumbled to dust and, with it, any means of using the ancient device again. Kelmaur knew it didn't matter: Cycerin was where he needed to be and his involvement with him was over.

He groaned. The expenditure of so much power had left him drained and his bones hurt where Cycerin's explosive teleportation had thrown him against the chamber wall. His ''near-sense'' was weakened and he stumbled several times, losing his footing on the slippery rocks and loose rubble.

As he reached the bottom of the slope he straightened his cloak and set off towards his tent, his strides becoming more confident as he found himself among more familiar surroundings.

Acolytes bowed as he passed, but he ignored them, too intent on rest and recuperation. As he ducked below the low entrance to his abode, painful cramps seized his stomach. Immediately he sensed the Warsmith's presence.

'You were successful,' said the Warsmith. It was a statement, not a question.

Kelmaur bowed extravagantly.

'Yes, my lord. The servant of the machine with but one hand has gone. The secret chamber was below the mountain, just as I had foreseen.'

'Good,' hissed the Warsmith, raising himself up to tower over Kelmaur. The sorcerer turned his head away, unable to look directly at the roiling metamorphosis of the Warsmith's face. The lord of the Iron Warriors reached up and cupped Kelmaur's chin in one massive gauntlet.

Kelmaur gasped in pain at the Warsmith's searing touch, squirming against his grip as black discolouration spread from where his master held him. The tattoos on his skull danced as Kelmaur cried out, his face contorted in agony.

'Now, Jharek, is there anything you wish to tell me? Anything you have kept from your Warsmith?'

Kelmaur shook his head. 'No, my lord!' he wheezed. 'I swear I have told you true every vision I have had.'

'Is that true?' asked the Warsmith, his disbelief plain. No answer was forthcoming and he sighed in feigned regret.

The Warsmith said, 'You achieve nothing by lying to me, Jharek,' and reached out his hand, pressing a burning palm against the sorcerer's temple.

Kelmaur screamed in agony as his flesh hissed and melted, filling the tent with the sickening stench of burned meat.

'You have one chance to live, Jharek,' promised the Warsmith. 'Tell me anything else you have kept from me and I will not kill you.'

'Nothing!' gasped Kelmaur. 'I have kept nothing from you, my lord, I swear! I see nothing more than that which I have told you!'

The Warsmith said, 'Then you are of no more use to me,' and exhaled a foetid breath of dazzling orange and green.

Kelmaur, already hyperventilating in fear, took a huge breath of the Warsmith's corrupt substance and began convulsing.

Kelmaur burned with horrific change and his screams were music to the Warsmith's ears. Evolutionary anarchy ripped through the sorcerer's frame. Kelmaur's body spasmed, grotesque changes warping through his flesh in a tornado of mutation. Tentacles, pincers, wings and other more unnameable organs burst from every part of his rebellious anatomy, his body now unrecognisable as human in the soup of aberrant growths.

Within seconds, all that remained of the sorcerer was a seething pile of pulped meat and bone, too grossly misshapen to survive.

'I promised I would not kill you, did I not?' sneered the Warsmith, turning and leaving the hideously mutated body of Jharek Kelmaur hissing in mindless torpor on the floor of his tent.

Amongst the gibbering ruin of distorted flesh, a single unblinking human eye stared out in horror and incipient madness.

The attacks on the walls continued for another three days, with thousands of men throwing themselves at the citadel and dying in droves. Casualties amongst the Jourans were lighter than on the first day, the weakest men having fallen in the early assaults.

On the third day, at the height of the attack, the embrasures were removed from the earthwork that ran the length of the third parallel and in a jet of exhaust fumes one hundred and thirteen Vindicator siege tanks moved into position and opened fire with an ear-splitting crack.

The walls of the citadel and bastions disappeared in a rolling bank of grey smoke and fire. Before the echoes had begun to fade, a second volley of shots battered the walls. Soldiers from both forces were pulverised in the massive barrage as shell after shell hammered the walls and breach.

Whole swathes of unstable structure tore free from the breach, hundreds of tonnes of rubble crashing downwards, carrying scores of men to their deaths and burying yet more beneath the falling blocks.

The bombardment continued for two punishing hours, undoing the repair work undertaken by the Imperial Fists and the Jourans to the ramparts. Hundreds died before they were able to take shelter in the bombproof shelters and the screams of the wounded carried as far back as the statue-lined road that led towards the Sepulchre. The face of the Mori bastion crumbled under the onslaught, tonnes of shattered masonry crashing into the ditch and forming a steep, but practicable breach. But by this time, there was no one left alive in the ditch to exploit it.

Broken by the twin blows of the stubborn defence of the Jourans and the betrayal of their masters, the Iron Warriors' soldiery turned and fell back from the walls in disarray.

As the bloodied survivors of the attack stumbled away from the citadel, shell-shocked and insane with terror, they broke and swirled around a giant figure in iron-black armour. A clear space surrounded the giant, who stood as still as a statue amongst the fleeing soldiers of his army.

The Warsmith marched through the mob, the soldiers parting before the bow-wave of corruption that travelled before him. He carried an arrow-headed icon bearing the skull-masked symbol of the Iron Warriors, which he planted in the blood-soaked earth at the edge of the ditch.

Leonid lowered his bloody power sword and watched the giant figure with a terrible sense of foreboding. Who this warrior was, he had no idea, but, instinctively, he feared him.

He turned to Corwin. The Space Marine Librarian's armour was scored with dozens of lasblasts, and blood ran from a gash torn in his upper arm.

'He is their Warsmith, the leader of this army,' said Corwin.

The Warsmith was well within weapons range, yet not one amongst the garrison could raise his gun to open fire.

They watched as the Warsmith pointed to the icon and then towards the fortress. Then he lifted an enormous axe from a shoulder scabbard and, in a rasping voice that carried the weight of ages said, 'You have until tomorrow morning to satisfy your honour and fall upon your swords. After that, your souls belong to me and I promise I will send every man alive within these walls to hell.'

The enemy commander's voice should not have been able to carry across the walls, but every soldier of the Jourans felt the terror of the Warsmith's words lodge like a splinter in his heart.