The Enduring Blade had become distilled insanity, everywhere the clamour of screams and blood and gunfire. Even encased once again in the comforting envelope of his helmet, even cradling the blocky meltagun he’d found decs before, the fear bubbled up in him and refused to cave in to an assault of meditation and litany. He was running scared.

Portals like great sucking lips opened on every side, smacking together wetly and disgorging their cackling cargo, ghost trails of warp and plasmic splatter following them.

Oh, he was scared of death, that much was true. Scared of pain and oblivion. Scared of the laughing black-armoured devils with their glowing eyes — so like the Space Marines yet so different. Scared of insanity and madness and rage. Scared of failure.

But more than that, scared of himself.

In his darkest dreams, in his soul, this was how he imagined the Mont’au. As he ran for the boardroom, hooves clamouring on the deck, wounded leg forgotten in the rush, he saw the ember-eyed hulks twisting to face him, pausing in their bloody carnage, weapons raised, and each time there came a hesitation: a split-raik’an pause in which, he knew, the armoured creatures were staring at his battered form, his blood encrusted wargear, his crater-dented helmet, wondering—

Which side is he on?

But he was gone and sprinting before the hesitation was over, and the gunfire was just a distant chatter at his back.

Ignore the screams.

Ignore the whispering.

Get to the ethereal. Save the ethereal. Focus. Concentrate.

The door to the boardroom wouldn’t open. Stomping footsteps closed in behind him. Something cackled nearby. Moving without thinking, he opened fire with the meltagun, dragging its slipstream of boiling air across the immovable bulkhead beside the door. A ruddy glow appeared wherever it touched, oxidising treatments skittering across the metal in a ballet of blue fire circlets. It was too thick to succumb to the assault.

A wide pipe above the sealed doorway clicked and clattered, bruised metal protesting at the conflicting expansion and contraction of its heating and cooling surfaces. Kais shrugged mentally and turned the gun on the conduit directly, its searing melta stream puckering and flaying the metal.

The thing behind him came around the corner.

The pipe ruptured and a flare of promethium flashed across his vision. The explosion hurled him off his feet, toppling him backwards. Everything tumbled downwards in his helmet display, a blur of metal and flame. His back found the deck with a breath-exploding thump, curling him over in a ball. A sheet of fire vomited overhead: a horizontal geyser of burning vapours sprouting from the ruptured pipe. The black-metal monster behind him shrieked as the fire lance struck it head-on, mashing it against the corridor wall like a swatted beetle.

Kais didn’t look.

Smoke and dust circulated all around, an opaque fog bisected neatly by the burning gas. He scrabbled beneath the flamespout on all fours, patting out the glowing speckles of singed fabric on his arms and legs. The door, absorbing the full force of the detonation, had ceased to exist.

Kais’s triumph was short-lived; he leaped into the boardroom with a shout, gun brandished hungrily before him, to find blood. Nothing but blood. Limbs off, heads removed, bodies slumped. Goggle eyes and gaping mouths, like fish.

El’Yis’ten stared at him reproachfully from a heap of flesh in one corner. Her body was on the other side of the room. Gue’la and tau, so scattered together that the bloodslick was a pale violet, a swirling galaxy of red and cyan running together. Here a tau arm lay, knuckles clenched, beside a de-limbed human corpse.

There was a symbolism here, perhaps. A sense of unity, a sense of physical sameness. Given a talented enough por’hui journalist, this scene might mean something. “In death, we’re all the same”, perhaps.

But it didn’t.

All it meant to Kais was a furious scrabble to remove his helmet, a bulge-eyed moment of staring around, unshielded by the layer of artificiality his HUD provided, and then a bilious surge of nausea from his guts to his mouth. This time he couldn’t keep it down.

His mind tumbled upside down, the whispering clogged his senses like mud and reality shifted like a compass.

Ardias stared at the madness around him, acquainting himself with the extent of the situation. That things had gone catastrophically wrong was undeniable: the peace negotiations were ruined and the hidden evil, Delpheus’s “masked fiend”, was exposed. Still, despite it all, despite the horror and the death, despite the utter collapse of events, Ardias entered the fray with an air of professional relish. He had been born and moulded to fight, and in so doing he justified his existence. It was a strangely reassuring notion, and he could see no point in denying it.

With a chattering bolt pistol in his hand, with a snarling chainsword cleaving the skulls of his enemies, it was difficult to appreciate the wider calamity — the physical realities were too close at hand to ignore. Ardias killed and shouted orders, commanding a meticulous purge, flanked by his indomitable, unwavering brethren.

Governor Severus had invited Chaos onto the Enduring Blade.

Chaos. The antithesis of order. The “Great Terror”. To investigate too far into the whys and wherefores of the Dark Power was to become clouded and tainted by it, so great was its potency. The mysterious agents of the Inquisition’s Ordo Malleus spent centuries struggling to bind and purge the madness, fully aware of the futility of conventional sciences and technologies. Instead the Taint, the very concept of Chaos, was embroiled behind a paradigm of religion and occultism, a stringent galactic code that stated clearly: the Emperor’s light is pure. All else leads to Chaos.

It was bound to the warp. It was bound to the real and the unreal together, it was bound to those things invisible in the mundane colours and clamours of materiality: thoughts, feelings, spirits and souls and angels and devils.

Chaos was a thing of division and conflict and contrast, a thing of anarchy and insanity. It would pull down the structures of humanity; of the universe; of time itself. It would shatter the galaxy for the reward of a pretty noise or murder a million billion men just to appreciate the hue of their fluids. It came from nowhere and went to nowhere.

It was everything the Ultramarines were not. Ardias exploded a chittering daemon thing, fluttering at him with hooked teeth bared, and thanked the Emperor for this holy opportunity to cleanse the taint. There were mistakes to be rectified here.

Ten millennia ago the Emperor’s glorious crusades to reunite humanity faltered and crumbled. The Space Marine legions, deified avatars of retribution and human endeavour, infallible in their purity and steadfastness, shining icons of strength and wholeness, had rotted from within. Like a worm ceaselessly and blindly hunting for a vulnerable entry point, Chaos had writhed its way into the very heart of the Imperium. Half the Space Marine legions were seduced and corrupted. Humanity held its breath. The Emperor all but died, sacrificing himself to save his race.

The Dark Legions scattered.

Ancient history, of course. Whispered lessons from the Librium at the Fortress of Hera. Arcane heresies guarded and studied by lexicaniums and codiciers and epistolaries. A blot on the data sheet, a stain on the purity of mankind. But the Legions were still out there, biding their time, murdering their way closer and closer to the heart of the Imperium. Who knew where they lurked, where they would strike next, where their shadow would fall?

Ardias snarled and swiped at a horned helmet so hard it exploded, unable to restrain the unnatural hatred and fury that rose in his gut, guiltily aware of the deviation of his thoughts from the measured approach that the Codex counselled.