Well figured I may as well post this here in case someone is interested.
Summary: This story follows a lone Black Shield named Karris as he is dispatched into a subterranean structure to learn the fate of an Ordos Xenos Inquisitor and her retinue. As he treads deeper in search of the agents he is stalked and hounded by the strange and nightmarish inhabitants of this realm. He will slowly discover the fate of each member of the retinue and finally that of inquisitor herself.
The ancient stone buckled and cracked beneath his boots with the force of the impact, the sound echoing endlessly into the darkness around him. Karris slowly rose to his feet. The landing had been harder than anticipated and he could feel the blood already clotting in several minor injuries beneath his armour. The world around him shifted through an array of colours as his helmet’s systems auto-cycled through filters and various spectra to optimise his vision.
+Brother Karris.+ The vox signal was faint and riddled with static. +…Brother Karris, report.+
He hesitated a moment and switched to thermal optics before activating his vox. Short-range vision returned. + This is Karris. The structure goes deeper than expected.+ He eyed the flickering readout his helmet offered - it must have been damaged during his descent. + Drop shaft is four miles deep. No sign of Inquisitor Virrak.+ Vox static filled his ears in response. +Repeat.+ More static.
The loss of communication was hardly surprising at this depth; the Inquisitor and her acolytes had also suffered communication loss shortly after their descent. Karris drew his bolter and began to move forward, his limited field of vision showing a rock strewn floor scarred and gouged as though dug by some ancient monstrous creature, the heavy grinding of ceramite on stone ringing out with each step he took.
Hours passed as Karris continued his advance through the chasm, the sound of his heavy footfalls the only audible noise in the darkness. Beneath his helmet, he grinned savagely to himself. They had been following for a while now, scuttling along the walls and ceiling behind him, more and more being drawn to the swarm, amassing against this new invader of their underground home. He wondered if the Inquisitor had noticed as the ranks of creatures had swelled in the darkness around her and her group. Had they heard the quiet scuttling of their legs, the gentle hissing of their breath, or noticed the faint flickering, right on the corner of their vision as one of the hunters had moved just a little too eagerly?
Perhaps not. It would have mattered little - even for trained agents of the Inquisition the swarm of xenos filth would have overrun them within minutes. At last Karris came to a halt. Instantly the scuttling behind him abated as the xenos slowed their breathing, no doubt assuming him to be listening. The silence in the chasm was almost deafening. He waited, and they waited with him.
Bellowing an oath, Karris whirled around unleashing a hail of bolter fire. Muzzle flashes illuminated the chasm around him in series of nightmarish scenes as each bolt drilled through the air seeking the flesh of the abominations. The detonations followed a split second later, each shell exploding with the force of a grenade as it impacted upon their leathery hides. The xenos shrieked as destruction tore through their ranks and the remnants of their brethren rained down on them.