With Kratch Doomclaw's decree issued, the pressure mounting within the Under-Empire reached its breaking point. For months, the Skaven had bred in the dark, their populations exploding in a hyper-accelerated surge. Now, the new generation had come of age.
Clan Rictus began its full-scale offensive.
The scarred surface of Vigilus was already a charnel house. It was a meat-grinder involving the forces of the Imperium, led by Marneus Calgar and bolstered by Ultramarines, Imperial Fists, White Scars, and the recently (and inexplicably) departed Dark Angels, alongside the Speed Freeks of the Orks, the Death Guard in the Dontoria Hivesprawl, and the Pauper Princes Genestealer Cult in Greigan Hollow.
Into this grand melee, the xenos force from the "unknown green fleet" that Calgar had dismissed months ago finally cast its lot.
In the Dirge Mast sector, the Astra Militarum had only recently managed to stabilize their lines, aided by the Knights of House Terryn and various Freeblades. Now, as the soldiers tried to rest in their trenches and ruined redoubts, a strange, persistent scratching sound began to gnaw at their sanity.
"What in the hell is that? Karl, go check it out!" Grumbling and sleep-deprived, a Sergeant dispatched a weary Guardsman to investigate the source of the noise.
"Right away, Sarge," Karl muttered. He hoisted his battered lasgun, its mono-molecular bayonet glinting, and trudged toward the sound.
Having never seen a rat in their lives, these humans had no frame of reference for the chittering symphony rising from the dark. Karl followed the noise to a sewer grate that had been sealed shut by fallen masonry.
"Coming from in here? Is it xenos, or...?" Trembling, Karl decided to bypass the grate. He jammed his bayonet into the ancient steel cover, slicing it like soft curd, intending to drop a frag grenade into the hole.
But before he could reach for his belt, the pitch-black, stinking depths of the sewer ignited with a thousand pairs of glowing crimson eyes.
"Squeak-chitter-screech!"
A flood of brownish-black fur and muscle erupted. Rats the size of small hounds surged upward, swarming over the Guardsman.
"AAUGH—HELP! SWEET EMPEROR—!!"
Karl managed only a single las-shot, vaporizing a few of the vermin, before he was dragged down. The only sounds remaining were the horrific tearing of flesh and the wet crunch of bone as the rodents feasted. Within seconds, the mound of vermin dispersed, leaving behind nothing but licked-clean bloodstains and the shredded remnants of flak armor.
Minutes later, the entirety of Dirge Mast was ablaze with floodlights. The piercing shriek of vox-sirens wailed across the sector. Small mushroom clouds bloomed as ammunition caches suffered secondary detonations, and countless civilians, Guardsmen, and even Sisters of Battle were dragged into the shadows by the black tide.
"Lord Calgar! Enemy contact, unidentified hostiles in all sectors!"
An Ultramarines adjutant delivered the report to Calgar, who had been awake for days orchestrating the defense. He was stunned. Had his lines been breached?
"Where is the breakthrough point? Dispatch the reserve to retake it immediately!"
Without a word, the adjutant handed him a handheld auspex. Calgar's eyes widened. The entire Dirge Mast sector was a sea of red alerts, from the refugee habs to the front lines, and even within the heavily fortified, opulent estates of House Agamemnus.
"Rally every soul still able to fight," Calgar roared, "Follow me!"
The Ultramarines, having repelled the initial verminous surge at their encampment, converged on their Chapter Master. Looking at the mangled, furry corpses of the rats, Calgar's face contorted with fury. "Whatever these foul things are, they shall face the Emperor's Wrath!!"
But Calgar did not yet know the scale of the disaster. It wasn't just Dirge Mast. The Death Guard in Dontoria, the Genestealers in Greigan Hollow, and every region on Vigilus where the Under-Empire had bored its tunnels were under simultaneous assault.
Only the continent held by the Adeptus Mechanicus remained untouched. The Cog-boys had dug so deep in their search for blackstone that the Skaven could not find a foothold in time and had simply bypassed them for easier prey.
…
At the Stygian Spires, the most vital water-reclamation site on Vigilus, the earth buckled under a catastrophic tremor.
The ground split and heaved like a see-saw. From the yawning chasm rose a massive, tiered mechanical platform the size of a dozen Baneblade tanks. Atop this rattling base, gripped by hydraulic claws, sat a colossal Warpstone bell.
Standing upon the bell was a figure draped in ornate crimson and white robes, clutching a staff topped with a rat-skull. From its head grew a pair of massive, recurved goat-like horns. This was the Chief Grey Seer of the Rictus fleet: Wenmoriqa Tox-tongue.
Beneath the bell, two massive, four-armed Rat Ogres gripped the iron chains of the clapper and began to pull.
"CLANG... CLANG... CLANG...!!!"
The Great Bell pealed, a sound that resonated through the very bedrock of the planet.
With the First Toll, a tide of vermin poured from every drain, ruin, and crack in the earth. With the Second Toll, the upright, starving Slave-Rats followed, their minds consumed by the Black Hunger as they threw themselves into the meat-grinder to pave the way with their corpses. With the Third Toll, emerald-green bolts spat from rusted, makeshift barrels, dealing death to everything in their path.
"Slay the xenos!" The Imperial Fists guarding the Stygian Spires swung their chainswords and barked bolter fire, meeting the swarm with unshakable resolve. Even as foul blood splattered their yellow plate, they did not waver. The rats gnawed frantically at their ceramite power armor to no avail as the Angels of Death pressed toward the bell.
CRACK-BOOM—
Emerald warp-bullets streaked through the air. Despite their superhuman reflexes, the Astartes could not dodge the sheer volume of fire. Ceramite that had protected these warriors for centuries was suddenly corroded and punctured by the mutating rounds.
"YES-YES! Kill-slay them! Slay the hairless-things!"
Hiding behind a wall of elite guards, a Skaven Warlord chattered incessantly. Clanrats armed with warp-muskets, resembling jagged, archaic rifles, advanced in a stuttering rhythm, squinting through beady eyes as they tried to use their comrades' bodies as living shields.
Finally, as the Thirteenth Toll echoed across the spires, Kratch Doomclaw himself led hundreds of thousands of Clan Rictus Stormvermin, supported by Moulder abominations and Skryre war-machines. The Great Skaven Horde surged toward the Spire, intent on seizing the greatest water supply on Vigilus.