Alessio Cortez felt no fear. It had been so long, he no longer knew what true fear felt like. When the call went up that orks had been spotted on the slopes, he felt only the familiar, welcome heat of battle-rush. His blood surged through his veins, flooding his muscles with everything they would need for the imminent combat. He felt the cardiovascular drumbeat in his gauntleted fingers where they gripped his trusty boltpistol.

Now they'll see, he thought. Now they'll pay for their arrogance.

He and his company had been charged with defending the Protheo Bastion from the lower ramparts, and, as the alien horde charged into view, they began pouring fire down onto the snorting, roaring front lines. The orks, usually disinclined towards night attacks, when their poor eyesight was rendered even poorer, carried flaming torches that made them all too easy to target. They had little chance of breaching the western wall. The chasm helped prevent that. But they had brought heavy armour with them, great lumbering artillery pieces with unbelievably wide muzzle, and, if these were brought within range, they would be able to lob their barrel-sized shells over the walls.

The 4th Company was not about to allow that.

Bolter-fire sputtered out, splitting apart the night, bright muzzle flares strobing across the walls. Lascannons cracked like lightning, ionising the air, lancing into ugly enemy tanks and cutting them apart as soon as they came into view. Explosions once again rocked the mountainside.

"For glory brothers!" shouted Cortez as he fired again and again.

Behind him he heard another voice boom out, "For glory, captain!"

Cortez glanced round for the briefest instant and saw a white skull. He recognised the voice, one of Tomasi's Chaplains, Brother Rhava, with two black-robed Sacratium acolytes in tow. Each acolyte silently carried a tray of extra ammunition and charge packs.

Rhava came forward and joined Cortez at the parapet, raised a glowing plasma pistol, and began firing burst after flesh-searing burst out into the crowded greenskin ranks where they were forced to halt at the chasm's lip. Many had already plunged over, struck by the fire of the Space Marines, or pushed to their deaths by overeager comrades.

"How goes the defence, brother-captain?" the Chaplain asked Cortez between rounds.

Cortez's clip ran dry. As he slid another from his belt, he answered, "There is little sport in this, holy one. They can't gain ground here. This assault is mass suicide."

"And yet," said Rhava between his own shots, "sport or not, you seem to be revelling in it."

Cortez grinned beneath his helm. "Tell me you find this a chore."

"It never is," said Rhava. Another of his blinding plasma-bolts struck an ork full in the chest. It sank to its knees, its chest little more now than a gaping crater of burned flesh. The ends of ribs poked from the side of the wound like stubby teeth.

There was a great roaring noise just to the north, and Cortez glanced that way to see another ship-killer emerging from its silo-tower, flames and smoke billowing up around it.

"I have heard," said Rhava, also noting the missile's emergence, "that The Crusader escaped successfully."

Cortez's eyes followed the missile's burning path. The power of such weapons was astounding. Part of him wished he could fly with it, to see the raw destruction it wreaked on whichever warp-damned enemy ship it struck.

"Ranparre gave everything to make it so," he said. "We will turn this around in his honour. Now that we-"

He never finished that sentence.

Something was wrong. One of the missiles from the other side of the fortress-monastery had suddenly changed vector.

No one would ever know what caused that change. Was it a simple malfunction? Sabotage? The will of malicious gods? No answer would ever come forth, but the results would be remembered in the Imperial history books for all time.

Rhava followed Cortez's gaze.

"By Dorn-"

The missile corkscrewed in the air above the Arx Tyrannus for a brief moment. Time seemed to slow down for Cortez as he watched, helpless to do anything. Then the missile plunged deep into the mountainside, its powerful thrusters forcing that armour-piercing nose-cone through metre after metre of rock.

The mountain shook.

Cortez and Rhava were thrown from their feet. Shouts of alarm replaced the stutter of gunfire on the air.

When the missile reached a depth of two-hundred metres beneath the rock on which Arx Tyrannus stood, it detonated, igniting the Chapter's ancient underground munitions stores one after another.

There was no time to shield oneself, no time to run, nor even to curse.

White fire engulfed all, and burned to embers the hopes of an entire world.

TWO.

"These were days so dark they had been rivalled only once in the history of the Chapter, and darker still were yet to come. But darkness is not a thing in and of itself. It has no form, no substance. It is merely the absence of light, and where light enters, darkness always recedes.

The smallest most ephemeral spark can grow to burn like a mighty sun.

It requires naught but the right kind of fuel. Snagrod gave us all the fuel we needed!"

-Brother-Codicier Ruthio Terraro of the Librarius,.

Crimson Fists Chapter, Adeptus Astartes.

ONE.

The Gorrion Wall, New Rynn City.

The concept of patience was as alien to the orks as they themselves were to the race of man. They did not hesitate, did not congregate around fires to hold war councils or to assess the success of their landing. They simply swarmed, and the outer fringes of the planetary capital, those poorest of districts that fell out with the city's grand defensive walls, were engulfed in fire and raw, rampant destruction.

Alvez and Grimm had been out on the southwestern ramparts of the Gorrion Wall for hours, overseeing the deployment of Crimson Fist resources to those sections of the city's outermost defences that were judged to be weakest. The rest of the city's perimeter, in particular those sections that were expected to hold longest, were assigned to companies of nervous-looking Rynnsguard. Alvez deemed this best for now, though a stout, high-ranking officer called General Saedus Mir protested as vocally as his respect for the Astartes would allow, adamant that his men would prove the equal of any blasted aliens. The first hour of battle, Alvez knew, would separate the real fighters from the cowards. He would pay particular attention to how the Rynnsguard handled their wall sections. Only then would he have an accurate idea of just what General Mir's forces were capable of.

The night sky was criss-crossed in every direction with arcs of orange light as ork craft poured down through the atmosphere from their warp-capable cruisers and destroyers. The city's fixed defences were taxed beyond capacity, firing almost non-stop, and the concussive waves of noise from each shot shook the air all around. Alvez saw a good number of the clumsily fashioned greenskin landers fall from the sky as burning junk, but there were simply far too many of them for it to make any real difference.

Squadrons of Imperial fighters and bombers screamed in overhead to engage those that got through, but the Rynnite pilots were woefully outnumbered. Though they killed a great many with their superior flying skills and lethal weaponry, the sheer number of greenskin fighters in the sky soon overwhelmed them. They would never return to the hangars at Targis Fields, never paint those well-earned kill-signs on their fuselages.

As he watched the aerial battles turn in favour of the invaders, Alvez said a grim prayer for the souls of the doomed Rynnsguard pilots. If the infantry and tank crews were anywhere near as brave, he decided, they might yet surprise him.

"You knew it would come to this," said Sergeant Grimm, standing at his side.

Alvez, dressed for battle in a massive suit of Tactical Dreadnought Armour- better known among the Astartes as Terminator armour-fingered the trigger of his twin-barrelled storm-bolter. The weapon was large, much larger than a standard bolter, and fitted with a heavy box magazine. They made a nasty mess of organic targets and its oversized bolts could rip through the side of a tank if they had to.

"It was always going to be this way, Huron. One rarely stops a Waaagh in space. You see all these craft? They are but the beginning of the green tide. By dawn, the land beyond these walls will be seething with alien filth and their machines."

"I'm glad you consented to evacuating the outer boroughs, my lord. I know it was a risk with the enemy already landing, but it was... the right choice."

Alvez sneered beneath his cold metal faceplate. "You mean it was the moral choice, Huron. Do not confuse the two. I am not a wasteful man. This siege will not be over quickly. We have lost control of local space. The enemy land in droves. Sooner or later, every man, woman, and perhaps even child, will be called upon to fight for survival. If evacuation saved the people of the outer boroughs tonight, it was only to postpone their deaths to tomorrow, or the next day. Be under no illusion. A great many sacrifices will be made here. But the Crimson Fists will remain standing."

An ork troop transport with a metal snout crafted to look like a fang-filled maw roared in low overhead, and Rynnsguard troopers on a neighbouring section of the wall instinctively ducked. The growl of its jets was deafening, and there was a wash of heat after it passed. Neither Alvez nor Grimm moved except to track the craft with their eyes.

Two powerful laser-defence towers hummed noisily as they locked onto it. Bright lances of light flashed out, ripping into the transport's hull. The stricken craft blossomed with bright bursts of orange fire and listed to starboard, but its momentum kept it soaring through the air until, seconds later, it smashed prow-first into a huddle of stocky, flat-roofed habs. The explosion lit the surrounding streets like a flare. By its light, Alvez could see thousand of orks charging along every street and alleyway, roaring insanely with battle-lust and waving all manner of killing implements above their ugly, misshaped heads.

"Ready yourself," the captain said to his second. "They must not set foot on the ramparts, nor breach the gates."

He ordered the rest of the Astartes on the Gorrion Wall to ready their weapons, and, all along its length, bolters were cocked, fat rounds sliding into empty chambers. He sent a short message to General Mir, authorising the Rynnsguard to begin the first Earth-shaker barrage, and was rewarded seconds later with the flash and boom of mighty long-guns as they claimed the first alien casualties of the opening battle.

Two squads of Crusade Company Terminators, Squads Zarran and Valdeus, had been tasked with holding New Rynn Spaceport with a full regiment of Rynnsguard in support. Alvez checked in with them now, and learned that the fighting around the spaceport, sixty kilometres away, was already intense. Sergeant Zarran had local command. He reported to Alvez that the spaceport's anti-air defences had claimed a great many enemy ships, but that enemy armour and infantry were massing in great numbers. Despite this dark news, there was a distinctive tone in Zarran's voice. It was a tone Alvez knew well: that of a man in love with his work. Zarran was looking forward to the slaughter to come.

As he should, thought the Alvez. The purging of xenos is righteous work.

The green horde boiling through the streets below the ramparts were almost in bolter range now. The captain stepped forward to the very edge of the rampart, pistons hissing as they powered the movement of his massive form. He raised his right hand and aimed the barrels of his storm-bolter down at the charging front ranks.

"Come, sergeant," he said to Huron Grimm. "You spoke of turning the Adacian red. Now that work begins."

Grimm joined him at the wall and, together with the forces stationed all along its many kilometres of length, they opened fire on the savage invaders.

In all the flashing light and smoke and noise, neither Space Marine noticed the brief, sudden brightening of the sky far to the east.

The first they knew of any catastrophe was when frenzied voices burst over the comm-link on a dozen different channels, all relaying the same information.

The Librarians were down. All of them.

The captain cursed.

"In Terra's holy name, what is going on?"

TWO.

Arx Tyrannus, Hellblade Mountains Pain woke Pedro Kantor. Something was yanking hard on his left arm, along the length of which a dozen fractures were trying to mend. His nerves sent fiery protests to his brain, demanding that he remain still while his body was about the business of healing itself. He heard a high-pitched growl of frustration, and the yanking took on a more frantic edge.

Kantor opened his eyes. There were red warning glyphs at the edges of visor display, but he ignored them, focusing instead on the cause of the tugging sensation. A short, sinewy form squatted on his left, its wrinkled green flesh naked but for a loincloth of poorly cured animal skin. Sharp teeth jutted from a mouth above which extended a long, hooked nose. Its beady red eyes burned with frustration.

It was a gretchin, and it clearly thought Kantor dead. It was trying to take Dorn's Arrow, but the relic storm-bolter was fixed tight to the back of Kantor's left gauntlet, and the ugly little xenos wasn't making any progress.

Despite the fractures, Kantor's arm moved as fast as a striking snake. He wrenched his wrist from the creature's long-fingered hands and grasped it by its scrawny throat, digging his fingers deep into its flesh.

The gretchin began to flail in panic and tried to call out to its fellows, but the vice around its throat permitted breath in or out.

Kantor squeezed harder, piercing the skin, feeling the tendons tear beneath it. Rivulets of alien blood spilled out over his hand. The gretchin's eyes rolled up into its head and its tongue flopped out. Its flailing ceased. Kantor felt vertebrae snap under his fingers and knew the creature was dead. He threw the body aside.

Where was he? What had happened?

One moment he had been firing down from the upper ramparts of the Protheo Bastion, the next, the world had turned white. He remembered Javier Adon frantically calling to him over the comm-link, but after that...

He turned and pushed himself to his feet. His suit registered elevated background radiation and several weaknesses in his cooling systems-nothing critical, but the latter would require the attention of the Techmarines eventually.

Dawn was breaking, but it was a dawn unlike any he'd seen on Rynn's World. The sky was an angry red. Rynnstar and her sister, Eloix, were hidden from view by great veils of smoke and ash. All around him, bright cinders danced and cavorted on the updrafts. Instinct told him he was facing west with the fortress-monastery at his back. He turned to look east...

...and almost dropped to his knees.

Utter devastation.

Even through the thick veils, he could see that the destruction of his beloved home was almost total. He stood on the far side of the western chasm, close to its edge, and beheld a scene his mind desperately wished to deny. Something had wiped Arx Tyrannus from the face of the planet. Whatever had done so had presumably thrown him clear across the chasm and onto the mountain's western slope.

Gusting winds momentarily drew the veils of ash aside, and Kantor saw that the walls, the gates, the bastions, tower and keeps, all were no more. Arx Tyrannus had been reduced to jagged spurs of steel and stone, jutting from the rubble like so many broken teeth. Here and there, he spotted familiar things in unfamiliar states, the remains of glorious works reduced to wreckage. He saw a great stone block standing tall among its shattered neighbours, its surface embossed with a pattern of carved skulls. It had been part of the towering north-western archway. Now it was part of nothing. To the right of it, he saw a figure in black marble, slumped awkwardly amid tumbled iron beams, its hands and head shorn off. He recognized it by the details on its chest. It was the statue of Isseus Coredo, a Crimson Fists captain who had given his life in battle two hundred years before Kantor had been born. The statue had stood in Memorial Hall, surrounded by worthy company. Now it had none, a lonely symbol that embodied loss, a symbol, Kantor realised, of his own disgrace.

I am the Chapter Master, he thought. It was my role to prevent this. Dorn, forgive me.

Curtains of ash and smoke closed over the view, and Kantor was almost glad of it. His hearts ached, and his limbs were numb with sorrow and disbelief. What was it that had struck them so hard? Had the ork fleet held some terrible weapon in reserve, knowing that the void-shields would fall when the Fists believed the orbital bombardment over?

Such questions were quickly put aside when he heard grunting and shuffling behind him. He spun to face the source of the noise, raising Dorn's Arrow as he moved. Visibility was extremely poor, the light of the suns interacting with the ash-filled air to cast little more than a dim red glow, but Kantor knew what he faced by their silhouettes alone. Three sturdy figures advanced towards him, large hands gripping heavy pistols and blades.

He didn't wait for them to see him. At a single thought impulse, Dorn's Arrow barked, and the silhouette in the centre spun and fell, bringing a yell of surprise from the throats of the other two. They had seen Kantor's muzzle flash through the smoke, and they raced forward, weapons raised, firing rounds that buzzed past his head like furious insects.

Kantor fired again, targeting centre mass, catching the ork on the right twice in the torso. The rounds detonated and split the creature's body apart. The last of the greenskin trio put on a burst of speed, racing out of the smoke directly at Kantor, eager to engage in close combat where the prodigious strength of its race would give it greatest advantage. Or so it thought.

Raw strength was so much less when wielded without skill. The ork's first wild swing-a lateral stroke intended to behead the Chapter Master with its large, chipped hatchet-was easy enough to duck. The blade whistled over Kantor's head. The instant it passed, he stepped forward, activating the energy field of the power fist on his right hand, and launched a lethal uppercut that cored the xenos beast like an apple.

Its hollowed form collapsed to the rocky ground, steam rising from the gaping cavity in its chest.

How many more of them were out here on the slopes?

They had been assaulting Arx Tyrannus in great number. Had the cataclysm devastated them, too?

Had any of his brothers survived?

Kantor tried to open a comm-channel, unencrypted, desperate to reach anyone at all, but his visor display reported too much interference from the residual energies of the great explosion. He removed his helmet, considering whether or not to call out. If the orks were still here in number, they would make straight for him with murder on their minds.

Let them come, he thought.

He would take whatever temporary comfort he could in dispensing death to them.

Clipping his helmet to his belt, he took a great lungful of air and was about to call out when he heard the distinctive sound of bolter-fire just off to the north. Without hesitation, he followed it. Was one of his brothers alive, or had some greenskin marauder simply salvaged a boltgun and was firing it at random into the air?

As Kantor moved north along the lip of the chasm, he saw a great many shapes on the ground. Most were orks, their heavy bodies burned black or pulverised by large blocks of stone thrown out in the blast, but there was a far sadder sight among them. With increasing frequency, Kantor came across the still forms of Crimson Fists lying among the xenos dead. They, too, had been thrown from the fortress-monastery's ramparts to land here, their bodies broken beyond their ability to heal. He wanted to stop, to check each for signs of life, but the sound of the boltgun was closer now, and he could see muzzle flare through the smoke up ahead.