'I can't hold on!' he yelled. The ledge crumbled at the edge, dirt and pebbles spiralling downwards to the plains far below.
'Don't let go!' screamed Leonid. 'Please!'
Uriel fought to hold on, but knew that he could not. Should he just let go? Surely the presence of Leonid would not affect their mission one way or another. He was a normal man amongst Space Marines, what good could he possibly do?
But before he could release his grip he felt a hand take hold of his shoulder guard and pull him back. Above him, Sergeant Ellard had hold of his armour and strained to pull him back. Uriel was too heavy for him to hold, but Ellard's strength was prodigious and held Uriel long enough for him to shift his grip to a better handhold with firmer balance. Centimetre by centimetre, Uriel eased himself back onto the firmer ground of the ledge and was able to deposit Leonid back onto the slope.
The colonel was hyperventilating, his face pallid from shock and terror.
'You are safe now, Mikhail,' said Uriel, deliberately using the colonel's first name.
Leonid took great gulps of air, keeping his eyes averted from the drop behind him. His body shook, but he said, 'Thank you.'
Uriel did not reply, but looked up to see a breathless Sergeant Ellard clinging to the rockface by what looked like his fingernails. Uriel respectfully nodded at the man, who nodded back.
'Sir, are you able to go on?' asked Ellard.
'Aye…' wheezed Leonid. 'I'll be all right, just give me a minute or two.'
The three of them waited as long as they dared before moving onwards, Uriel in the lead with Ellard bringing up the rear. The colonel's steps were hesitant and unsure at first, but eventually his confidence returned and he made good time.
The journey down the mountains blurred into a painful series of vignettes: traverses across terrifyingly narrow spurs of rock and heart-pounding drops onto splintered ledges. Uriel continued down the slope of the mountain, pressing himself flat against the rock until he felt a tap on his shoulder and looked around to see that he had reached the base of the shear in the rock, that he was on a wide, screed slope of ash and iron debris. A churned mass of broken earth sloped gently to the darkened plains below.
The warrior band were spread around, breathless from their climb, and as Uriel looked up to see Leonid and Ellard completing the descent, his admiration for their endurance and courage soared as did his shame at the thought of even considering letting Leonid fall to his death.
Ardaric Vaanes approached him and said, 'You made it then.'
'You were right,' said Uriel. 'That was not easy.'
'No, but we're all here. Now what?'
That was a very good question. They were still many kilometres from the fortress, and Uriel could not even begin to guess how many enemy soldiers lay between them and its lower slopes. He scanned the ground below him, picking out scores of work parties and earth-moving machines hauling hundreds of tonnes of earth to build the ramp that led towards the fortress. A hissing lake of molten metal pooled at the base of the slope, bathing everything in a hellish orange glow and the rumble of engines and cursing voices drifted up from the construction sites.
'You know there's no way we can just walk through that many soldiers. Even if the vast majority are only human.'
'I know,' replied Uriel, eyeing the huge bulk-haulers. 'But perhaps we will not need to.'
The heat radiating from the molten lake was stifling, filling the air with stinking fumes and making each breath hot and painful. Uriel edged around a tall mound of piled steel sheeting and waited for the latest work party to shuffle past, chained together at the neck by spiked collars and dressed in filthy rags. Servants of the Iron Warriors in all-enclosing vacuum suits shouted gurgled commands to the slaves, beating and whipping them as they pleased.
The rumble of heavy, tracked bulk-haulers and booming gunfire covered the Space Marines' approach down the lower slopes of the mountain, the darkness of the smoky clouds only helping them to approach the construction site unobserved. The huge machines were bigger than the largest super-heavy tank Uriel had ever seen, controlled via a cab mounted high on a massive, tracked engine unit that pulled a huge container on wheels with the diameter of three tall men.
Laden with tonnes of earth and rock, they plied their stately way up the ramp before depositing their cargo on its forward slope and then turning around and making their way back down again to refill. Millions of tonnes had already been poured out, yet the ramp was barely halfway towards the upper levels of the fortress. Uriel watched as a trio of bulk-haulers made their way towards the bottom of the ramp, and turned to Pasanius.
'They're coming,' he whispered through his armour's vox unit.
'I see them,' confirmed Vaanes.
Across the construction site from Uriel, he could see Vaanes climbing the side of the ramp, gaining height from where he could use his jump pack to better effect. Other Space Marines were poised ready for the word to attack.
The first of the bulk-haulers completed its wide turn and ground off into the smoke for more earth and Uriel bit his lip in nervous anticipation.
'Second one's almost round,' said Pasanius, and Uriel could sense the anticipation in his sergeant's voice.
'Aye,' he nodded. 'Ready?'
'As I'll ever be.'
'At times like this, I wish Idaeus was still here,' said Uriel.
Pasanius chuckled and said, 'This attack would be just his kind of thing.'
'What? Against impossible odds and with no recourse to the Codex Astartes?'
'Precisely,' said Pasanius, nodding in the direction of the ramp. 'Last one's down.'
Uriel returned his gaze to the hauler as it described a wide arc at the bottom of the ramp and the massive machine turned towards the fortress. When the cab had levelled out, but the huge trailer portion was still curved around, he rose to his feet and shouted, 'Go! Go!' over the vox and ran out into the open.
Scattered groups of slaves looked up at them as they ran for the enormous machine, but otherwise paid them no mind. Up close, the bulk-hauler was even larger than it had first appeared, fully nine metres tall and constructed of dented sheets of thick iron and bronze girders. Its wheels were solid and tore deep furrows in the ground as it rumbled onwards. Fortunately, it was still moving slowly enough to catch and Uriel leapt for the iron ladder that led to the cab above.
Space Marines jogged alongside the bulk-hauler and clambered onto the mnning boards, beginning to climb the craggy sides of the trailer. Uriel swiftly ascended the ladder towards the platform bolted to the side of the driver's cabin, hearing a heavy thump of something landing on the cab's roof. Metal tore and he heard screams.
He continued climbing, seeing the door above him burst open and a creature in a vacuum suit and leather harness emerge from the interior of the cab. Harsh, static trills of fear emitted from a copper faceplate as it saw Uriel, but he didn't give it time to react, reaching up and gripping its harness.
It tried to draw a pistol, but Uriel pulled hard and sent it spinning from the driver's cab to the ground below. Kyama Shae, the Crimson Fists Space Marine riding the running boards, shot the mutant in the head and the groups of slaves clustered around this part of the ramp cheered as it died.
Uriel scrambled up the ladder and swung into the driver's cabin, ready to fight, but saw that there would be no need. Another two creatures, clad in the same black vacuum suits as the one Uriel had thrown to the ground, lay dead in their bucket seats, torn open from neck to groin by Ardaric Vaanes's lightning claws.