'You have sited your batteries well, Forrix,' noted Honsou.

Forrix nodded briefly, accepting the compliment. 'I do not believe we need to dig any further. To do so is pointless - we would expose ourselves needlessly to airbursting shells and the slope of the promontory will obscure the walls of the fortress should we press forward.'

Honsou saw that Forrix was correct. 'What about the batteries at the foot of the mountain? This will be well within their ideal range and the guns here will undoubtedly be targeted.'

'I realise that, Honsou, but when our guns are in place I will lead warriors from my company to take the enemy gun positions by storm.'

Honsou narrowed his eyes, aware that Forrix had called him by his name for the first time. Then the notion that he would be denied the chance to capture the guns he had discovered hit him and he snarled, You will capture the lower guns? I discovered them, the honour of their capture should be mine!'

'No, Honsou, I have another task for you.'

'Oh, and what would that be? Keeping the guns fed with shells? Guarding slaves?'

Forrix said nothing and pointed to a gap in the trench wall that was filled with sandbags and defended by a full squad of Iron Warriors.

'When the time is right, you will lead the storming parties from this point and take the breach. You will hold it until the human soldiers are able to scale the rock face and escalade the walls with ladders and grapples.'

Honsou opened his mouth to retort, then snapped it shut as he realised the honour of the task he was being given. His chest swelled with pride before his natural cynicism and suspicion came to the fore.

'Why, Forrix? Why do you do me this honour? You have done nothing before now but deride me and keep me in my place as a mongrel, a half-breed.'

Forrix was silent for long seconds, as though he himself did not know exactly why he had made such an offer. He turned from the mountain and faced Honsou.

'There was a time I thought like you do, Honsou. A time when I believed we fought for something more important than simple revenge, but as the millennia of battle ground on, I came to realise that there was no point to what we did. Nothing ever changed and nothing brought us closer to victory. I have been too long from the field of battle, Honsou, and as I watched you fight the Imperials, I knew that in your heart, you are an Iron Warrior. You still believe in the dream of Horus, I lost my hold on it many centuries ago.'

Forrix grinned suddenly. 'And the fact that it will send Kroeger into a towering rage.'

Honsou laughed, feeling uncharacteristically charitable towards the venerable Forrix.

'That it will, Forrix, but he will be shamed by your decision. Are you sure you are wise to antagonise Kroeger in this way? He descends further into the grasp of the Blood God with each passing day.'

'The young-blood is nothing to me. I see nothing for him beyond mindless slaughter, but you… for you I see great things. The Warsmith does too, I see it every time he speaks to you.'

Honsou said, 'In that I think you are mistaken. He hates me.'

'True, and yet you lead one of his grand companies' pointed out Forrix.

'Only because Borak died at Magnot Four-Zero and the Warsmith has not yet named his successor.'

'Again true, but ask yourself this: how long ago was the Battle at Magnot Four-Zero?'

'Nearly two hundred years.'

'Aye, and do you think that in all that time the Warsmith could not have found someone to lead the company?'

'Obviously not, or he would have done so.'

Forrix sighed and snapped, 'Perhaps that tainted blood of yours has made you as slow-witted as Dorn's lap-dogs from whence it comes! Think, Honsou. Had the Warsmith named you Borak's successor there and then, would any of his warriors have accepted you? No, of course not, and nor should they have, because to them you were just a despised half-breed.'

'Not a lot has changed, Forrix.'

'Then you are more foolish than I took you to be,' snarled Forrix, marching back along the trench to the supply depots and leaving Honsou confused and alone in the half-finished battery.

The machine temple at the heart of the citadel pulsed with barely contained power as though the very walls themselves breathed with an inner life or sentience. Its structure was strangely organic, though the chamber was built in honour of exactly the opposite.

The mass of the chamber was filled with baroque machinery that infested the space like a gigantic coral reef, steadily growing and increasing its mass with every passing year. A sickly amber glow permeated the chamber, alongside a low, throbbing hum, just at the threshold of hearing.

Shaven-headed technicians and servitors in faded, yellow robes wandered like ghosts through the bewilderingly complex labyrinth of machines, their ministrations to the holy technologies ritualised over thousands of years to the point that any true purpose had long been forgotten.

Regardless of their function, the rituals and blessings applied to the machines served their purpose: keeping the chamber's sole inhabitant alive.

Arch Magos Caer Amaethon, Keeper of the Sacred Light, Master of Hydra Cordatus.

Lodged atop a tapered rhomboid at the chamber's centre, the flesh of the arch magos's face - all that remained of his organic body - was suspended in a gurgling vat of life-preserving fluids. Ribbed copper wiring trailed from behind the skin, twitching wires stimulated the atrophied muscles of his face. Clear tubing pumped oxygen-rich nutrients through his ravaged capillaries and the fragmentary scraps of cortex that were all that remained of his brain, the rest having been replaced and augmented with kilometres of twisting corridors of logic stacks.

Amaethon's features creased as twitching electrical impulses awoke him to the fact that he was being addressed.

'Arch Magos Amaethon?' repeated Magos Naicin, taking a draw on a smoking cheroot. The smoke gusted from his back, whipped away as the recyc-units cleared the arch magos's chambers of their pollutants.

'Naicin?' asked Amaethon hesitantly, the fleshy lips having difficulty in forming the words. 'Why do you disturb my communing with the holy Omnissiah?'

'I come to bring you news of the battle.'

'Battle?'

'Yes, master, the battle above on the surface.'

'Oh, yes, the battle,' stated the arch magos. Naicin ignored Amaethon's lapse in memory. For six centuries, Amaethon had been linked to the beating heart of the citadel, monitoring every facet of its operation and that of the cavernous laboratorium hidden beneath it. For the last century of that service, he had been unable to leave this sanctuary, steadily becoming more a part of the citadel as each portion of his body withered and died. Soon the old man would be gone completely, his bio-engrams broken down and reduced to nothing more than task instruction wafers to be fed into worker-servitors.

Naicin knew Amaethon's fragile grip on reality was slipping, and it was a rare moment when he was able to summon up enough memory to interact with others. The first flush of panic when the invaders had attacked had galvanised the arch magos into remarkable lucidity, but even that was beginning to fade.

'The battle,' repeated Amaethon, a fragment of his crystal memory reacting to the word. 'Yes, I remember now. They come for what we protect here. They must not have it, Naicin!'

'No, arch magos, they must not,' agreed Naicin.

'How could they even know of its existence?'

'I do not know, master. But they do, and we must make plans in case the citadel's defences do not hold the invaders at bay.'

The flesh of Amaethon's face bobbed in its amniotic suspension. 'But they must, Naicin, this citadel was built by the finest military architects of the day, there are none who can breach its fastness.'