Fetid water dripped down the bleached white shoulder guards of the advancing Space Marine. Lights affixed to his shoulders and the side of his helmet dimly illuminated the slimy walls of the sewer tunnel, and the forms of his brother Marines, a few paces in front. The pilot light from Brother Falsavius' flame thrower flickered gently in the dampness.

The squad came upon the first sign of their quarry. An eight-pointed star was etched into the wall, slime leaking into the grooves.

"Chaos," Brother-Sergeant Eulexes hissed. The very word filled his mouth with a bitter taste. "May the spirit of Dorn be avenged on this day." He whispered. He lightly caressed the imperial cross on a chain around his neck, the symbol of his Chapter, the Black Templars. His mind went to the most recent passage of scripture he had etched into his armor. It was on his right shoulder guard.

"Scio proditor, contemno proditor, caedo proditor."

Know the traitor, hate the traitor, kill the traitor

"Truer words hath never been spoken," Eulexes said under his breath. He turned to his squad, and spoke into his intercom so as not to be overheard. "Brother Falsavius, take the point."

The black-armored Marine nodded and re-lit the pilot of his flamer. "Yes, Brother-Sergeant."

"The rest, thou shalt follow closely behind me. Our enemies art not far now."

A murmur of assent crackled back to Eulexes through the radios.

As they walked through the knee-deep muck, silently as a passing wind, Eulexes could almost hear the humming commotion from the hive-city above. It extended for miles above them, to the surface of this world, and miles beyond that. It's highest spires reached into the stratosphere. Tethered to its' peak was an orbiting stardock. The population was over twenty billion, and not a one had any idea the vile taint that was spreading through the Underhive. The planetary governor had called for an Inquisitorial inspection of the problem. The Black Templars had responded before the Inquisition even received the telepath.

"Through the destruction of our enemies do we earn our salvation," Brother Gaugamus recited.

"Amen," A chorus of voices answered silently as they advanced.

Eulexes felt a surging inside of him. It was not hatred, it was not mindless bloodlust. It was a righteous fury, a desire to carry out the Emperor's will in His name. He knew the same fire burned in the breasts of his brothers. It burned in all Black Templars, always flickering like the small glow from Falsavius's flamer. Today, he would let it become a blaze.

They turned a corner, and knew they were nearing their target. Three bodies had been mutilated, hung from chains with their arms outstretched and their empty eyes staring into the blackness above.

Brother Gaugamus's voice sounded disgusted. Eulexes could hear the hatred. "They dare mock the position of Saint Celestine. She was martyred in that way."

"No amount of foul mimicry can ever mar her image, in any eyes," Eulexes said. "Every soldier of the Emperor prays for a chance to follow in her footsteps."

This seemed to calm Gaugamus, but he quickly recited the Hymn Of Cleansing. His brothers joined him, the familiar words flowing over their tongues and seeming to bring peace to the mangled bodies before them.

"Now," Eulexes said, "Let us bring His judgment,"

"We are the servants through which His will is done," They recited.

As they walked away, Eulexes turned again to look at the heretical totem.

"Brother Falsavius," He said.

"At once, Brother-Sergeant," He growled, raising his flame thrower. A roar like a chorus of gods filled the sewer tunnel. In a few searing seconds, the gruesome display had been cleansed. The charred remains dropped into the fetid water and flowed through the drains in the walls, even deeper into the network.

More and more totems and icons were passed as the minutes ran long and time itself slowed to a halt. This far underground there was no dawn, nor dusk, nor day nor night. Only a perpetual dim twilight filled with dampness and the screams of the cursed animals who inhabited this dark under-realm. Still the Marines plowed on, as impervious to the fear of this place as they were to it's foulness. Their armor kept the putrid water away from their bodies, and their backpacks filtered the fetid air into the oxygen-rich mix that all Space Marines require. The squads heavily armored gloves were fixed on the grips of their boltguns. They were hungering for revenge, for release, and for a chance to continue their ten thousand year crusade.

And then, echoing off the slime-slick walls of the sewer tunnel, they heard chanting. Far removed from the pious litanies of those walking in the Emperor's grace, this arcane prayer filled the marine's hearts with bitter hatred. They were worshippers of the Chaos god Khorne. Lord of murder, bloodshed, and hatred. They were the ones who murdered the civilians, who mutilated their bodies and exhibited them as offerings to their foul god.

The marines fanned out, spacing themselves precisely to avoid friendly fire. Falsavius moved to the front, to cause maximum damage to the enemy while harming none of his comrades. Eulexes spoke into his vox-caster.

"Thy bolters deliver the Emperor's judgment. Recall thy training, use short, controlled bursts to purge His enemies. Thy chainswords and knives shall cleave out their dark hearts, but mind thy targets. To slay one of the Emperor's servants is to invite eternal damnation, to slay His enemies is to invite eternal salvation."

"Yes, Brother-Sergeant," They echoed back.

"We face our enemy today, directly, looking into their foul eyes, and we shall defeat him. In the name and way of Dorn, we shall find our victory on this day."

"Yes, Brother-Sergeant,"

They came to a grate, opening to a large chamber lit by orange firelight. Shadows danced on the walls, human forms barely recognizable as such, the chanting now audible and the marines heard it was a guttural language, a language of sin and hate. It was not the holy High Gothic. It was a language gifted to the cultists by their god. None of the marines could bear the sound, and pious Gaugamus' fury could be felt by his brethren.

"Let us purge these abominations," He growled.

Eulexes motioned to Cassander, for he carried the breaching charges. "Brother Gaugamus is right, the time for vengeance is now. Let us breach this grate and deliver that fury from the Emperor's hands."

Cassander began to place the charge, while Eulexes continued to give orders. "When the grate hath been breached, Brother Falsavius will enter and cleanse the room. Doth this plan agree with thou, Brother?"

"It would be an honor to be the first to fight, Brother-Sergeant," Falsavius said levelly.

"Who will be the second?"

"I will accept the challenge," Brother-Corporal Antochus said, unsheathing his chainsword.

"All of thee will follow, singly, but spread thyselves around the room as soon as you enter. Remember: mercy is weakness. The mere presence of any mortal within that room would expose them to the corruption of Chaos, and they must be purged."

"Yes, Brother-Sergeant,"

"Activate the charge, Cassander, when we are clear." The marines moved back from the grate, away from the blinking light of the charge upon it. They knelt, whispering last rites and prayers, beseeching the Emperor for the strength to overcome their enemies.

A final word from Cassander, and a deafening explosion racked the slick walls of the sewer. Molten gobbets of rock rained down upon the marines, sizzling ineffectually on their obsidian armor. Falsavius charged through the flame, chainsword roaring, and Antochus was right on his heels.

"For the Emperor!"

The rest of their brothers surged through the breach, amid the screams of the dying and the roars of Falsavius and Antochus, their chainswords spraying their enemies' blood on the walls, seeping through the unholy carvings. Explosions sounded as frag grenades ricocheted off the walls, showering the cultists with lethal, hot shrapnel.

The interior of the room was streaked with dried blood. Mutilated corpses were hung from the ceiling, their faces locked in a final rictus of indescribable pain. Candles illuminated the room, which was no more than a large crossroads between sewer tunnels. Filth flowed freely, mixing with blood. The stench was no so much in the marine's olfactory sensors, as in their souls. Every aspect of their being was repulsed and disgusted by what they saw. Falsavius had sheathed his chainsword, now using his flamer to cleanse the area. Bodies writhed in the muck, burning intensely. The promethium adhered to their corrupted skin, offering them as little mercy as the dark warriors who dispensed it.

Eulexes executed three quick slashes across the chest of one of the heretics. He fell, his screams drowned and garbled in the blood that poured out of his mouth. The Sergeant spun and fired into a mass of bodies, muffled explosions from the exploding bolt rounds separating arms from torsos, heads from necks, souls from bodies.

Marines advanced slowly. The heretics had erected a small barricade at the end of a room. Their bolters spoke, singing praises of battle and mimicking the vows the marines chanted. The explosions from the bolts set the barricade ablaze.

Ineffective fire from autoguns and laspistols pattered off the marine's armor. The screams of the dying only encouraged the marines to fight harder. Falsavius, now using his bolt pistol again, fell into the ritual of battle. Aim, prayer, fire, kill, aim, prayer, fire, kill. All of his shots found their marks, and he never failed to hit his target directly in the forehead.

Gaugamus was firing from the hip, chanting prayers of battle in a monotone. His bolter thundered with the songs of the heavens, trails of fire marking the bolt's path to its' target. Suddenly, an incredibly powerful force slammed into his chest. He toppled to the ground, darkness slowly seeping into his vision. He saw Eulexes' helmeted face over him.

"Brother, how dire art mine wounds?" He asked softly.

"Thou art in thine holy Emperor's care, Brother," Eulexes said. The gaping hole in Gaugamus's chest was oozing black fluid, shrapnel from the grenade had shredded the flesh, and Gaugamus was pouring enriched blood into the muck. Bullets and bolts were whining overhead like angry hornets.

"Brother-Sergeant, am I worthy of the Emperor's peace?"

Eulexes chambered a bolt in his pistol. A round ricocheted off his shoulder pad, but he didn't notice. "Many times over,"

A single shot to the eye plate ended Gaugamus's service. His entire body relaxed, and Eulexes knew the Emperor had taken him into His care.

The marines vaulted over the barricade, Antochus decapitated the heretic with the grenade launcher who had taken Gaugamus's life.

The heretics fell back, very nearly running before the marine's assault. Rounds slammed into their backs, throwing them to the floor. With screams of fury, the pursuing marines sank their knives into their backs, twisting them before ripping them out. Agonized screams echoed on the walls as the cultists' spines were torn out.

One last heretic remained. He clutched his bloodied sword in white-knuckled hands. His terrified eyes followed a figure emerge out of the flames and smoke. The other Templars were arranged in a line, firing-squad style, their bolters pointed directly at him. The very ground shook with the marine's advance. Around him, the bodies of his fellow cultists were motionless, the expressions on their faces mimicking the horror of their victims. He backed away from the malevolent form approaching him, his boots sinking into the muck. He felt it trickle inside, soaking his feet. His revulsion was only matched by his terror. The marine advanced through the burning sewage, heedless. Behind him, his squadmates still retained their bolters trained on the traitor's form, absolutely motionless.

"P - Please, G-Great One. . . I - beg - for-" The marine started suddenly and cuffed him. The comparatively tiny man reeled backwards, the yelp of pain that escaped his lips impeded by the broken teeth now embedded in his tongue.

"Speak not, foul heretic!" Eulexes boomed, "Lest thy taint infect the minds of my brethren. Though, truly insidious thy words must be to pass through their faith and fortitude." The silence and stoicness of his brothers emphasized that fact.

The traitor fell to his knees in the sludge, clasping his hands together. Eulexes was disgusted to see the tattoos on his palms matched each other: the eight-pointed star of Chaos. The sword he had been holding clattered uselessly to the ground, slowly rolling into the stream and being swallowed by the sewage.

Heedless of the marine's proclamation, the heretic spoke again, blood seeping from his brutalized mouth, and yet he pleaded still. "I wish to forsake the ways of Chaos! Allow me to repent, and I shall once again walk in the light!" He would have said more, but a power-armored boot hit him in the stomach. He doubled over, groaning in pain and despair. Another blow hammered him across the neck, and he flew two meters and fell into the muck.

He struggled to his knees, desperately trying to keep an eye on his attacker, though one of his eyes was ruined, pouring blood mixed with filth over his face, into his mouth. The urge to vomit almost overcame him.

Eulexes strode over to his prey. With a single, fluid motion he drew his bolt pistol, a flick of the wrist, and a hollow click, and a round was chambered. He aimed directly at the mark of Khorne on the heretic's forehead.

"Please. . ." The wretch wailed.

Eulexes looked down, no mercy in his veiled eyes.

"Caedo proditor. . ."