At the far end of the chamber, a wide, semicircular cog-toothed door sat half open, a small group of people clustered around it.

Leonid immediately recognised Magos Naicin and the ungainly form of two Praetorian battle-servitors. Servitors were surgically altered slaves utilised by the Adeptus Mechanicus for a variety of manual tasks. Praetorians fulfilled the adepts need for heavy defence, featuring an augmented slave body atop a mechanised track unit, with a variety of lethal weapon combinations implanted in the servitors' arms.

The last figure was unknown to Leonid, but he was astonished at the hideous bulk of the man that not even his shapeless robes could conceal. His skin was the colour of black steel, his face more dead than alive.

Naicin saw them coming and darted through the door, dragging the enormous robed figure after him.

Leonid growled in anger and set off towards the closing door as the two battle-servitors rumbled forwards. Leonid was too intent on the door to pay them any heed. Nothing would prevent him from reaching Naicin and killing him.

The first Praetorian raised its weapon arms as Leonid's honour guard rushed after him, realising his danger. The fastest man of the team dived for his commander, knocking him to the ground as the Praetorian opened fire, the rhythmic thumping of a massive bolter filling the chamber as it hosed the chamber with shells.

The shells passed over Leonid, but the men behind were not so lucky. Three were thrown back, huge holes blasted in their chests. Leonid and his rescuer rolled into the cover offered by a huge tracked drilling rig as more shots filled the chamber, heavier auto cannon shells blasting metal chunks from the machine.

A flurry of las-blasts struck the Praetorian, which rocked back, bloody craters torn across its body. The battle-servitor didn't slow, it merely adjusted its aim and ripped apart yet more of Leonid's guard with deadly accurate gunfire, bullets spewing from the gun at a furious rate.

The man who'd saved Leonid's life spun from the cover of the drilling rig, taking careful aim at the Praetorian's head. He dropped as he was struck in the head and chest, blown apart by the mass reactive bolter shells as they detonated within his flesh.

Leonid scrambled away as the heavy bolter and auto cannon began tearing up the chamber. Glass, plastic and blood erupted all around, showering them with sparks as soldiers and worker-servitors went down, panels and glow-globes shattering.

The lobotomised worker-servitors were not programmed to react to such external stimuli and continued working at their posts. They died silently as the Praetorians walked the shells into them, raking their fire left and right, servo assisted muscles easily absorbing their guns' huge recoil.

Emergency lights flickered on as fluorescent panels were shot out and Leonid slithered towards Eshara, who had drawn his crackling power sword.

Human workers scrambled to disconnect themselves from their stations and seek shelter as the battle-servitors slowly advanced towards them. One dropped to his knees, begging for mercy.

The Praetorian shot him in the face.

The rest died in three controlled bursts of fire.

Leonid surged from behind the drilling rig as the wounded Praetorian finished the slaughter of the technicians. He squeezed off two rounds and the servitor staggered, two massive holes blasted in its skull. It raised the heavy bolter and fired as Leonid's third shot took it in the throat, blowing its head clean off.

It fell backwards, firing the gun as it toppled, stitching a line of bullets towards Leonid and clipping his shoulder. He yelled in pain, the impact spinning him to the floor.

The second Praetorian trained its auto cannons on Leonid, the firing mechanisms whining as they built up speed to fire.

Before it could shoot, Eshara leapt from the cover of the crate and slashed his sword through the barrels in a bright explosion of sparks. He spun on his heel, hammering his elbow into the battle-servitor's face and smashing its skull from its shoulders in a welter of blood. His reverse stroke hacked the organic top half of the Praetorian's body from the track unit. The whine of its weapons motor sputtered and died.

Leonid picked himself up from the ground, clutching his wounded shoulder, and nodded his thanks to Eshara before turning the closed door behind which Naicin and his unknown accomplice had vanished.

'Damn!' he swore. 'How in the name of Joura are we going to get through that?'

Eshara looked over Leonid's shoulder and indicated something behind him.

Leonid frowned and turned to see what the Space Marine was pointing at. And grinned.

The door to the Machine Temple was thirty centimetres thick and composed of solid steel, but it crumpled like tinfoil when the eighty-tonne drilling rig slammed into it. The roof section was torn free by the low clearance of the door as it came screeching through, spewing torn scraps of steel and sparks all across the inner sanctum of the Machine Temple. The giant tracked machine slewed around as Eshara lost control for a second, the enormous rig smashing into a bank of monitors and control panels. The amber-lit chamber was filled with pulsating machinery and barely had the drilling rig skidded to a squealing halt than Leonid, Eshara and the four surviving members of his honour guard leapt from the rambling machine.

Leonid grunted in pain as he landed, trying to make sense of the scene before him.

Magos Naicin stood with his head bowed beside a squat, rhomboid structure topped with a shattered vat of draining fluid. In one gloved hand he held his bronze facemask and, in the other, what looked like a glistening slab of wet meat. He tossed it aside and Leonid was horrified to see the slack features of Arch Magos Amaethon staring up at him from the floor. After centuries of service, the organic remains of the arch magos were finally dead.

The bulky figure that had accompanied Naicin stood atop the rhomboid, its wide, misshapen arms spread wide. Bulging motion undulated beneath its robes as though a collection of snakes writhed beneath them. Even as he watched, the robes split and fell from its body, revealing a massive, iron-black musculature that rippled in a horrific amalgamation of organic and biomechanical components. Was this creature machine or man, or some horrific symbiosis of the two?

'Naicin!' shouted Leonid. 'What have you done?'

The magos lifted his face and Leonid gasped in horror as he saw Naicin's true features, a swirling mass of thin, wormlike tentacles that glistened and writhed together to form the mass of his head. A cluster of milky and distended eyes bulged in the centre of his features, above a sphincter-like mouth, ringed with needle teeth.

'Mutant,' spat Eshara, raising his pistol.

The four Guardsmen were transfixed in horrified wonder at the bizarre sight before them. And their perverse fascination killed them.

The figure atop the rhomboid raised its arms, its flesh writhing as they transformed into two massive-barrelled weapons. A roaring crescendo of fire erupted from the weapons, blasting through Leonid's honour guard and disintegrating them in a heartbeat. Leonid once more dived for cover behind the drilling rig as Eshara charged towards the giant figure at the chamber's centre.

Magos Naicin hissed and leapt to intercept him, moving with inhuman speed, his arms whipping out and toothed proboscis erupting from his fingertips to smash Eshara from his feet. Hissing ichor splashed Eshara's shoulder guard, the ceramite plates of his armour rapidly dissolving beneath it. The Space Marine captain rolled beneath the questing mouths as Naicin came at him again, hissing acids spraying from his lashing, whip-like hands.

Leonid took advantage of the distraction to rest his pistol against the track guard of the drilling rig and take aim at the monstrous figure that had killed his men.