Unnatural Selection

The following is a short story from the official Eternal Crusade website.

## Stories

Noxious purple mist clung to the rocks, leaving a glistening residue that was sticky to the touch. Sergeant Castor stood and wiped his fingertips on the discoloured leaves of tall grass lining the gravelled path. Little more than a goatherd’s trail from the high peaks of the mountain to the few settlements clustered on its median slopes, it had been travelled recently, but not by the goatherd or his animals.

‘Tyranid?’ asked Hellar, his heavy bolter slung low at his waist. The rest of Castor’s Ultramarines, eight battle brothers and four scouts in the cobalt blue armour and gold trim of the second company, awaited his verdict.

Castor nodded. ‘Without doubt.’

‘They’re near,’ said Gudrik Skraemir, bent low over the path farther down the slope. A fetish-hung shotgun and an ice-rimed axe were slung crosswise at his shoulders. The Space Wolf’s helm was slung at his belt, and his resin-stiffened hair was spiked behind him like an ocean predator’s fin. His braided beard was threaded with beads and bone, making him look like some feral world shaman, as did the many tattoos curling over his cheeks and forehead. He drew in great lungfuls of tainted air as he all but crawled on his belly over the rocks.

Like a stalking predator.

‘A blind man could see that, Fenris-born,’ said Scout Sergeant Varrio, his gaze never once leaving the scope of his sniper rifle. He scanned the sectors behind and to their flank as his three scouts completed the watch circle. Varrio’s disdain at Gudrik’s methods was clear, but the warrior hadn’t yet steered them wrong.

‘Aye, that he could,’ replied Gudrik, springing to his feet and spitting a mouthful of phlegm. ‘Which begs the question of why Castor here asked me to join your pretty band.’
‘Because wolf-sense is keener than any sight of ours,’ said Castor, before Varrio could retort. ‘Let that speak for itself.’

Varrio shrugged, unwilling to concede, but knowing better than to show dissent before outsiders.

‘I fought alongside the Wolves on Ichar IV,’ continued Castor, ‘Their warriors led us true when no others could, when even Telion lost his way.’

The younger scouts drew in startled breaths at so unlikely a scenario, but Castor had seen it with his own eyes. Trapped beneath the industrially scabbed surface of Ichar IV, surrounded by maddened tyrannic organisms and with no line of retreat, only a lone wolf whose name Castor never learned had found a route to the surface.

‘What makes you so sure the beasts are establishing a hive anyway?’ asked Varrio.
‘Because I’ve seen this pattern of behaviour before,’ said Castor. ‘On Armageddon. When tyrannic organisms lose their synaptic connection to the hive mind they revert to base instinctual desires. They nest, they hunt and behave exactly like animals.’
‘The attack on the communications array was not the work of animals,’ grunted Hellar. ‘Too well co-ordinated to be random.’
‘And it wasn’t the only one,’ said Castor. ‘Which means there is likely to be a hive trying to form somewhere in these mountains.’
‘Does Protus agree?’ said Varrio, nodding towards the summit of the mountain, where Castor’s fellow sergeant held the communications array they had so recently relieved.
‘He will,’ said Castor.

Gudrik led them from the path and across a scree-covered slope of broken stone and gravel. Cold winds blew from the high valleys, yet the acrid mist stubbornly clung to the slope, as if leaking from somewhere far below.

Despite his best efforts, Castor’s every step sent avalanches of fist-sized rocks tumbling downhill. Gudrik moved without leaving so much as a footstep to mark his passage.

Patches of rough gorse and sickly bracken dotted the slope, hardy grasses sickening with unnatural toxins. More proof, were proof needed, that the mountains were host to something obscenely alien.

The Space Wolf held up a fist and the Ultramarines halted, keeping low to the ground and readying their weapons. Gudrik sniffed the air, then closed his eyes and bent to press his ear to the rocks. His lips moved in a wordless oath known to huntsmen all across the ice of Fenris.

The Space Wolf’s eyes flicked open, and Castor saw his yellowed irises flare. Gudrik bared his fangs, focusing his gaze upon a cluster of rocks thirty metres ahead.

At first, Castor thought the Wolf was mistaken. Then saw undulant forms moving in the mist. Too many and too occluded by the rocks to get a reliable count. At least a dozen, but most likely more. Glossy carapaces, sliced with blade impacts. Grotesque, bulbous heads filled with tearing fangs; bodies rippling with scythe-edged hook limbs.

Hormagaunts.

A surge of battle-stims gathered in Castor’s system, ready to instantly transition him from rest to combat readiness.

The creatures appeared to be unaware of their presence, too fixated on something obscured in the mist. Varrio and his scouts had their sniper rifles at the ready and Hellar held his hand over the firing mechanism of the heavy bolter.

‘Wait,’ said Gudrik. ‘These won’t be the only ones.’

Castor nodded. He’d already begun quartering the landscape to find another swarm.

‘There,’ said Varrio, aiming his rifle at a host of shapes moving along a partially hidden river bed steaming with frothed alien vapours and roaring with the sound of an unseen waterfall. ‘Below them.’
‘Another swarm-pack,’ said Gudrik. ‘Two score creatures at least. The first group are outriders, guardian creatures.’
‘Then what are they guarding?’ said Castor, adjusting the filters on his auto-senses to better penetrate the fog wreathing the stream bed.

Immediately, he saw Gudrik’s assessment of their numbers was conservative. At least forty, with something larger at their centre. He consulted his eidetic recall of currently codified tyrannic organisms, but came up empty. The beast’s misshapen form was a gestalt hybrid of pallid flesh, chitinous plates, vestigial pseudopod limbs and bowed legs swollen to elephantine proportions.

‘What in the name of Guilliman is that?’ hissed Castor.
‘You’re the prodigy of Cassius,’ said Hellar. ‘You tell me.’

Castor glanced over at Gudrik, who shrugged and said, ‘Not anything I’ve ever seen, which is a good enough reason to kill it as any.’

The creature’s ruggedly ovoid skull was distended, but not with any natural growth patterns. Its shape was uneven, rugose with tumours and misshapen with uncontrolled mutation.

No, not uncontrolled.

Unconsciously accelerated. Competence without comprehension.

‘Hyper-evolution,’ said Castor, thinking back to a beast Chaplain Cassius had described killing in the frozen reaches of Armageddon’s polar wastes. A creature likewise afflicted by myriad hideous cranial mutations.
‘What?’ said Gudrik.

Castor’s mind raced as he articulated his theory as it formed in his mind. ‘The swarm needs to establish a connection to the overmind,’ said Castor. ‘And in response to isolation, their gene-strands trigger mutations in each new iteration of creatures. They cycle through a host of evolutionary avenues in a massively compressed time period, hoping to eventually hit upon the required mutation that causes hive-synapses to form.’

The Space Wolf grinned and racked his shotgun.

‘Then let’s make this an evolutionary dead end, eh?’

Castor picked his target, a creature with one eye-socket that was little more than a sliced ruin. Across the iron sights of his bolter, the wound appeared to have been caused by a claw.

Internecine conflict brought about by territoriality?

An avenue to explore at a later date, but Castor would settle for simply killing the beasts just now.

‘Two volleys, advance to cull,’ said Castor. ‘On my mark.’

Affirmative icons appeared on his visor almost instantaneously. Gudrik just nodded.

‘Mark,’ said Castor.

The mountainside lit up as eight mass-reactives punched into the guardian swarm. Armour-piercing tips blasted through the organic plates of the hormagaunts and exploded within them. Screeching cries echoed from the mountainside. Chugging blasts from Hellar’s flanking heavy bolter ripped across the hormagaunts, enfilading the line of alien monsters. Castor saw at least six explode in quick succession.

Varrio’s Scouts felled four more with silent spits from their sniper rifles and Gudrik’s shotgun cratered a hormagaunt’s thorax to a jellied mass of shredded meat.

A second volley tore through the beasts, and more alien creatures collapsed to the rocks. The Ultramarines split into two combat squads, the first led by Castor, the second by Varrio. Castor ran crouched low, keeping his bolter aimed into the smoking mass of ruptured flesh and bone. The iron sight slipped left and right, but nothing remained alive.

Gudrik moved effortlessly ahead of him, moving over the loose rocks with inhuman agility. A youth spent on an inconstant world of ice and ever-shifting landscapes had given him preternatural balance.

Castor vaulted the rocks in which the tyranid creatures had concealed themselves. He scanned for threats. Gudrik stamped down on an alien skull, then spun and brought the butt of his shotgun down on another with faultless economy of lethality.

A hormagaunt missing its body below the thorax writhed in a morass of pulped entrails. Even in death it sought to kill him. Castor didn’t break stride, shooting it in the head as he passed.

‘Clear,’ he shouted as Gudrik sliced the lower jaw from a spasming creature and slung it from his shoulder guard.

The scouts took position on the rocks as Varrio and Castor led the combat squads down to the river bed. The pack below had increased speed, screeching and bounding towards the revealed waterfall. Only the lumbering creature at their centre kept them from simply leaping beyond the reach of the vengeful Space Marines.

Only now did Castor see how large this pack truly was.

At least fifty beasts, broad of shoulder and sinewy of limb, with elongated hook-claws and curled, dew claws. Brutes of the genus and powerful killers.

‘Don’t let them reach the waterfall,’ shouted Gudrik.

Castor was about to question that when he saw the outline of a cave entrance behind its thundering waters. The arcologies of Arkhona were rumoured to be unfathomably deep and curiously resistant to cartography. Any creatures that reached the darkness beneath the world would never be seen again.

A narrow gorge of scum-frothed water churned with toxins and bio-acids at the base of the falls. At its centre was a spur of black rock, scummed and pitted by corrosive acids.

‘Hellar, Varrio; pin the pack in place,’ ordered Castor. ‘Circle sweep to kill. Gudrik, with me. I will go high, you follow in the water. We shall meet in the centre.’

The Space Wolf grinned as he saw what Castor intended.

‘We shall be as the hunters of the hrosshvalur!’ he yelled, leaping into the pool and howling with feral glee.

More gunfire blazed through the purple mist behind Castor and Gudrik. Mass-reactives raked the river bed and sniper fire punched through skull after skull. Fully half the pack had turned to engage the suppressing Ultramarines.

Half would have to do.

Castor ran along the edge of the gorge, gaining height with every powered step. Below him, the Fenrisian clove the water like a blade, his shotgun firing into the escaping tyranids with relentless precision.

The ground continued to rise, and Castor suddenly veered to the side. He leapt from the edge of the gorge and landed on the tall spur of rock at the centre of the pool without missing a stride. Thirty metres below, two dozen hormagaunts surrounded the mutant synapse mutant. It bludgeoned a path through the water, keening in blind animal panic as it sought to reach safety.

Castor sprinted to the end of the spur, drawing his combat blade and hurling himself from the rock. He slammed down hard on the mutant beast’s shoulder plates. It screeched in anger and bucked with the colossal impact, rolling its chitin-armoured skull.

Slick with bio-secretions, Castor had no chance of keeping hold, but he had no intention of remaining on its back. Castor slid clear, rolling onto his front and punching his combat blade into the bony shield of armour plating at its neck.

He swung his legs around, using the momentum of his enormous weight to drag the creature down with him. The mutant beast’s knees buckled as Castor hauled it over its centre of balance. They crashed down, throwing up a tsunami of polluted water as its malformed skull hit the water like a ploughshare.

Castor was thrown clear, fighting a fleeting disorientation as he fought to get his legs under him. He rose from the waist-deep pool, combat blade in hand as the mutant beast reared up in a cascade of dark water.

Its hormagaunt protectors threw themselves at him. He killed the first with a blade-thrust through its jaw, the second with an elbow smash. A third died with its throat ripped out in his fist, a fourth with its hissing face pulped by a crashing headbutt.

Claws raked his armour, envenomed fangs skidded over his visor and bio-toxins burned the ceramite of his battle plate. The water churned with alien blood as Castor fought with every weapon, every limb. He broke bones, smashed skulls open, calling upon every lesson taught by Cassius’s tyranid hunters to slay this vile foe.

An ululating howl echoed from the sides of the gorge, and even the tyrannic monsters paused in their assault at the terrifying sound. Castor looked up and saw Gudrik Skraemir haloed in the light of the sun.

Like Castor before him, he leapt from the spur of rock, having climbed it from within the pool. But where Castor had only sought to delay and pin the beast in place, the Fenris-born aimed to deliver the death blow.

His ice-rimed axe glittered with killing light as it swung for the synapse mutant’s neck. Frost-forged steel split the unclean flesh of the mutant creature, cleaving meat and bone like the softest clay.

No executioner ever swung a finer blow, no butcher ever made a deeper cut.

The monster’s head screeched even as Gudrik sheared it from its body and black blood jetted from the stump. It crashed into the water, bloated limbs thrashing as its nervous system died. The hormagaunts died with it, shrieking in pain as synaptic feedback ripped their imperfectly-linked minds apart.

The Space Wolf landed in the water beside Castor, his stiffened hair hanging lank at his cheeks. A huge grin split his face, and his fangs were red where he’d chewed his lip bloody.

‘A good kill, Brother Gudrik,’ said Castor. ‘Chaplain Cassius would have approved.’
‘A slaying worthy of a telling by the skjalds, Brother Castor,’ agreed the Fenrisian with a booming laugh. ‘And that leap of yours? We’ll make a Skyclaw out of you yet.’