Uriel released Pasanius and moved from warrior to warrior, shouting at them as he went, his voice growing louder as he warmed to his theme.

'Do not forget who you are!' he yelled over the furious whispers. 'You are Space Marines. Warriors of the Emperor of Mankind and you fight the Dark Powers wherever you find them. You are strong, proud and you are warriors. You have fought for centuries and your honour is your life, let none dispute it!'

He drew his sword and activated the blade, which rippled with fiery energies, and raised it high.

'Every foe we slay means something!' shouted Uriel, slashing at the walls of the tunnel with every word. 'Every battle we win means something. We mean something! Remember every battle you have fought, every foe vanquished, every honour won. They stand for everything we were created to serve. Remember them all and the voices will have no power over you!'

The slithering carvings within the walls screeched in frustration, retreating into the depths of the rock before Uriel's bright blade as his words undid their masquerades. A new sound arose to banish the hateful whispers: the sound of voices being raised in honour of great victories of the Imperium.

The Storming of Corinth, the Iron Cage, Phoenix Island, the Liberation of Vogen, Armageddon, the Fall of Sharendus, the Eleggan Salient, the Battle of Macragge… and a hundred others rang out against the foul temptations of the voices, the walls becoming dark and solid as the volume of the warrior band's shouts grew.

Uriel almost wept in triumph as the darkness of the walls retreated and the illusory nature of the tunnel fell away to reveal the softly glowing exit before them. The soulless light of Medrengard filled the tunnel and though it promised nothing but death and emptiness, Uriel rejoiced to see it.

'This way!' shouted Uriel, scooping up his bolter before staggering exhaustedly towards the tunnel's exit.

The warrior band gathered their weapons and followed him from the hellish mouth of madness.

Once clear of the tunnels of despair, Uriel saw that they had barely penetrated the walls of the fortress at all. The Iron Warrior with the coruscating energy whip had called this place Khalan-Ghol, and as Uriel cast a wary glance towards the hungry maw of the tunnel they had just left, he wondered if it was a name given to the fortress or one it had taken for itself. A potent malice saturated the air, a sense of ancient sentience lurking in the very rocks and mortar of this place.

The Space Marines, Colonel Leonid and Sergeant Ellard collapsed as they fled the dark of the mountain, shaking their heads clear of the last vestiges of the tunnel's evil. It had led them out onto a high ledge at the head of a long, winding set of carven black stairs overlooking the madness of the interior of Honsou's fastness.

Sprawling towers, manufactories and darkly arched cloisters jostled for space amid tall statues and spike-fringed redoubts. Dark-tiled roofs and insane structures of non-Euclidian geometries that hurt the eyes and violated the senses were crammed within the jagged, hostile architecture of the fortress, twisting, and gibbet-hung boulevards winding between them in impossible ways. A wan emerald light held court over it all, pierced with streamers of sickly orange fires burning from forges and melancholy temples. Streams of liquid metal ran in basalt troughs through the fortress, the reflected heat bathing everything in droplets of glistening, metallic condensation.

Copper, verdigris-stained gargoyles vented clouds of steam and tall, crooked towers of black brick spewed choking clouds of pollutants into the atmosphere from great, piston-heaving power plants. Grey figures shuffled through the city and dark, slithering things slipped like shadows through the nightmare streets of the fortress towards the heart of the mountain, where a single, rearing tower of iron stood, its dimensions immense and impossible.

It speared the clouds above, a swirling mass of bruised vaporous energies circling its tallest peak. Thousands of arched firing slits pierced the tower, its base out of sight behind the belching forges clustered before it. Uriel knew that the master of this horrible place must dwell within that awful tower and understood with utter certainty that this was their ultimate destination.

Flocks of the delirium spectres wheeled above the dread tower, their raucous cries echoing weirdly from its tall spires and nameless garrets. Tall peaks of the black mountains swooped high above them, and though it had seemed they walked for many kilometres through the rock of the mountain, the noise of the battle was close, as though they had travelled only a little way.

'How can that be?' said Vaanes, guessing Uriel's thoughts.

'I don't know,' replied Uriel. 'We cannot trust that our senses are not deceived at every turn in this dark place.'

'Uriel, listen, about that tunnel and the things that were said…'

'It doesn't matter. It was the voices, they got inside us and made us say these things.'

Vaanes shook his head. 'What were they? Daemons? Ghosts?'

'I do not know, but we defeated them, Vaanes.'

'You defeated them. You saw through what they were trying to do to us. I almost gave in… I wanted to.'

'But you had the strength to defeat them,' said Uriel. 'That came from inside you, I just reminded you of it.'

'Maybe,' said Vaanes, in a rare moment of confession. 'But I am weak, Ventris. I have not been a Space Marine of the Emperor for many decades now and I do not think I have the strength to be one again.'

'I believe you are wrong,' said Uriel, placing his hand in the centre of Vaanes's breastplate. 'You have heart, and I see courage and honour within you, Vaanes. You have just forgotten who you really are.'

Vaanes nodded curtly, pulling away from his touch without replying, and Uriel just hoped he had been able to convince the former Raven Guard of his own worth. This hellish place would test them all to the very limits of their courage and would seek out any chink in their armour and destroy them if they let it.

He caught Pasanius's eye, but his friend broke the contact just as quickly, turning his back upon Uriel.

'Pasanius,' said Uriel. 'Are you ready to move on?'

The sergeant nodded. 'Aye, there's no telling what might follow us through those tunnels. The sooner we're gone the better.'

Uriel reached up to stop Pasanius as he moved off. 'Are you all right, my friend?'

'Of course,' snapped Pasanius, pushing past Uriel and marching to the top of the winding, uneven stairs. Smooth, black and glassy, they would require careful negotiation if they were to avoid slipping and breaking their necks.

Pasanius led the way down, the Space Marines and the two Guardsmen following gingerly in single file. The clanking workshops of the fortress spat flames and smoke: the pounding of hammers the size of tanks echoing from the blackened walls of the windowless buildings. But over everything hung the leaden weight of the spirit of the iron tower, its dead-windowed stare crushing the soul by its very existence.

As they descended into the fortress, Uriel saw strange creatures of light moving between the vast structures, tall, elegant beings walking on golden stilts that trailed streamers of lambent amber fire. Bizarre carriages were suspended between them, filled with glowing ripples of light and a swirling latticework of cogs and pistons. A procession of these creatures passed through the fortress, but they were soon lost to sight in the illogical maze of the streets.

Huge bulldozers, similar to the bulk-hauler they had commandeered, rumbled through the wider thoroughfares, red and hateful, with tall banner poles hung with eight-pointed stars and iron tenders hitched behind them. Blood sloshed from the tenders, leaving a filthy stream of red in their wake as they made their way from the fighting on the walls to the tower at the centre of the fortress. Twisted limbs jutted from the blood-filled tenders, the corpses in each one jostling against one another as the bulldozers ploughed onwards. As the bodies moved, it was clear from their size and muscle mass, that they were those of Iron Warriors.