The story can be about anything providing that its vaguely pre-heresy or great crusade-era in nature. Here is a story I have written for it, concerning an issue which I think is central to the World Eaters as a legion:
---------------------------------------------------------
‘Drip..... Drip...... Drip.....’
Warule sat entranced by the steady stream of condensation as it fell from the roof and rolled down one wall, pooling near the feet of the crouching form of Sergeant Buseyt. Though the liquid was stained and clouded it reminded him of something else; of blood, of the way which the crimson fluid stuck to a surface until sufficient weight forced it through gravity to descend, forming in rivulets and pooling like mercury. Its faint reflective aspect represented in a myriad of colours and shades, the mirror image of another world. But the water which crept morosely down the wall was very much of this reality, a sorry contrast to the dominant white and blue of the Astartes crouched throughout the room. Poor comparison to faded red, the remains of stained blood not entirely removed.
“Make yourselves ready, cohort!” The harsh digital representation of Buseyt’s voice chimed in Warule’s earpiece, breaking him from his reverie. Instinctively he gripped the haft of his chainaxe, running his gauntleted thumb over the well worn activation rune. Lime-green diagnostics winked positive in his visor; compartmentalised diagrams of his turbofans at once became opaque and then disappeared as the systems in the device were checked by the control centre of his armour. Warule had seen each and every step on a hundred occasions and anticipation built in him as it moved through its sequence: Auto-senses, environmental integrity, power levels, each confirmed in turn until only a single system remained. The diagnostic interface, as if sensing the weight of occasion, paused for a moment before an image of opened fangs enveloped the cross section of his mk3 helm; His Bio-neural implants were ready. The image faded, leaving Warule’s image intensifier staring once more at coarse granite and pool of discoloured water.
When Buseyt spoke again, this time in more measured tones, it came to Warule as if he were submerged beneath that thin film of water and in another world. Flat, undisturbed, a shade of nothing; “Ignatov is pinned down in those ruins two hundred metres ahead. Machine gun nests, a trench, heavy machine weapon fire.” the Sergeant’s words came broken and halting. Despite the digital translation, all of them well knew the crushing sense of anticipation inherent in his tone. The sense of eagerness mixed with fear. After what seemed like an eternity he spoke again, but this time the words rushed forth like a torrent, bursting to come out, “We attack from above. For Angron. For the Emperor.”
A pause.
A drip of water.
The hollow echo of his breath faded into silence, and it hung in the air for what seemed like an eternity.
“Activation code...”
The world that existed around Warule collapsed, and the man that was the Astartes did not hear that final half muttered utterance. A torrent of images cascaded through his mind, a bursting flash of memories and experience which flowed through him, fleeting, never giving him respite or chance to reflect: Of the blood red skies of Lalonde, Brother Gasker lying in his arms his life blood draining away, Commander Dreyt falling to the Reavers, The howls of his brothers caught in the Maelstrom of Iskar slain without pause, Of blood, The training camps of Bodt a thousand white glowing gauntlets held to the sky fists clenched and the galaxy their prize. The images faded to the background, decades of war, of death and destruction, condensed into a heartbeat. There and gone like the flash of bolter muzzle.
With a scream of exaltation the faded world of greys fell away from him and the veils which cloaked his vision were discarded as he burst through the surface of that sterility. To Warule it did not matter that special biological pre-cursors had been activated, that carefully targeted hormones and chemical programs were being released into his brain. That reservoirs of adrenalin and more exotic components were being dumped directly into his bloodstream.
It did not matter. At that moment it felt like lightning had struck him. As if tens of thousands of volts of electricity were arcing through his body, as his muscular frame arched and threatened to tear itself loose from his skin of armour and launch itself through the ceiling. Twin hearts hammered in his heaving chest like pistons, his helmet desperately struggling to pump air into his lungs fast enough as they heaved in great undulating and ragged gasps. As his teeth clamped together, threatening to splinter apart, he gripped the haft of his chainaxe; it roared to life, the scream of its serrated blades echoing the fire which coursed through his veins. His eyes bulged, dancing wildly and rolling backwards in their sockets with a crazed intensity. He barely noticed his brother marines in front of him, seemingly wrestling with their own invisible daemons as their bodies were wracked with the tremendous forces raging within. Ceramite strained at the seams as they stumbled out of the building, those too inexperienced not to have loosened the bonds on their armour joints now paying the price; wracked with pain as their hyper-extended musculature expanded and bulged within their armour.
Warule bounded after them in great strides, barely able to keep his footing as his legs drove him forward, chain-axe singing its chorus of death and destruction. A serrated blade symphony which occupied his attention entirely, precluding any moment other than the one he now lived in.
Moments later they found themselves in an open space of sand covered pavements and roads. Warule’s heart sang at what was to come next and he thundered to a halt beside his squad, sending chips of dirt tumbling through the air. Placing his arms by his sides he planted his feet into the ground and squatted. He looked up into the red-tinged hue of the sky. To Warule it looked as though scarlet clouds drifted amidst the falling blood of his colleagues. Of Gasker, of Dreyt, of every World Eater who had ever fought and fallen.
Diagnostics blinked positive and screams of exaltation sounded in his earpiece as with a thunderous roar the turbofans in his jump pack ignited. His armour shook, feeling as though it would tear itself to pieces and with an almighty and ear splitting crescendo he was launched into the sky in a corkscrewing trail of black smoke and ozone.
Towards his enemies, towards blood and destruction, towards that world which existed so fleetingly and to which he always longed to return.