The moment Rimuru and the Deathwatch marines crossed the threshold of the gateway, the world behind them seemed to vanish. The massive, wound-like portal did not close, but the blighted plains they had just crossed were gone, replaced by an oppressive, fleshy wall that sealed them in. They were no longer on a planet; they were inside a stomach.
The interior of the Citadel of Contagion was a fever dream of biological architecture. The corridor was a tunnel of pulsating, sickly green flesh, ribbed with arches of blackened bone. The floor was a squelching membrane, and the only light came from the bio-luminescent glow of giant, weeping pustules on the walls. The air was thick and wet, and the tolling of the great bell was now a deep, resonant thrum that they could feel in their chests, a slow, patient, and eternal heartbeat.
"Reality is thin here," Corvus's voice warned over their private vox channel from the Obelisk. "The daemon's will shapes this place. Trust your faith, not your senses."
As they advanced, the citadel began its assault. The fleshy walls shimmered, and the corridor was suddenly filled with a vision of a peaceful garden on Macragge, the Ultramarines' home world. A fallen battle-brother, one who had died on the Space Hulk, stood there, his face serene and whole. "It is over, brother," he said to Captain Arken. "The fight is done. Come, rest with me. The Emperor grants us peace at last."
"Lies!" Arken roared, the single word a detonation of pure faith. "The Emperor grants us only the duty of war! That is our peace!" He raised his thunder hammer, and the illusion flickered and died, revealing the grotesque, fleshy tunnel once more.
They pushed deeper. The floor beneath them dissolved into a sucking, filth-choked mire. Before the Astartes could sink, Rimuru took a step forward. He did not fly or create a bridge. He simply willed the ground to be solid, and it was. The mire beneath his feet hardened into black, glassy obsidian, creating a safe, clean path for the others to follow.
"He twists reality," Rimuru noted, his voice calm and analytical. "But his control is… emotional. He projects what he thinks you want to see. Do not engage with the illusions. Simply ignore them."
<
The world shifted for Rimuru. The fleshy, pulsating walls became transparent overlays, revealing the true structure beneath: a fortress of corroded iron and ancient stone, simply covered in a thick layer of daemonic growth. He could now see the true path, a straight, direct line to the heart of the citadel.
"This way," he said, taking a sharp turn down a corridor that, to the Astartes, looked like a solid wall of weeping intestines.
"Tempest, that is a dead end," one of the marines cautioned.
"No, it isn't," Rimuru replied. He walked forward, and the fleshy illusion parted before him like a curtain, revealing the dark, iron hallway beyond.
The Deathwatch marines followed, their trust in the being now overriding the lies of their own senses. They were walking through a haunted house with a guide who could see the backstage machinery. The whispers and temptations of Nurgle continued, but they lost their power when their guide so clearly saw them as nothing more than cheap tricks.
As they approached the center, the psychic pressure grew immense. The tolling of the bell was deafening. They entered a vast, circular antechamber, and there, blocking their path, were the final guardians. They were not a horde, but a trio of Plague Drones—gargantuan, fly-like daemons mounted on buzzing, demonic engines, their riders chanting praises to Nurgle as they leveled plague-spewing cannons.
"The final test before the master!" Captain Arken bellowed, raising his hammer. "Death to the daemonic filth!"
The Deathwatch engaged them in a furious, close-quarters battle. But before they could be bogged down, Rimuru acted. He raised his left hand, and a web of black, shimmering threads shot out, wrapping around the Plague Drones. It was Universal Thread.
"Hold still," he commanded. The threads tightened, and not only were the daemons immobilized, but the foul energies that powered them were being drained away, consumed by Rimuru's own power. The daemons shrieked as their connection to Nurgle was siphoned, their forms flickering and destabilizing. A single, final swing from Arken's hammer was then enough to shatter the lead drone into a cloud of fading motes.
With the guardians dispatched, they stood before a final set of doors. They were made of colossal sheets of pitted, verdigris-covered bronze, bound with bands of stretched, tattooed skin. As they approached, the doors swung inwards with a deep, groaning sound, the tolling of the bell reaching a deafening crescendo before falling utterly silent.
They had arrived.
The throne room of Vorlag the Vile was a grand, circular cathedral of contagion. The vaulted ceiling was held aloft by pillars of fused spinal columns. A stagnant, misty lake of iridescent filth formed a moat around a central island, upon which sat a throne of diseased iron and weeping fungal growths. Piles of skulls, lovingly arranged by size and decay, served as decorations.
And on the throne, sat the Daemon Prince.
He was a hulking behemoth, a monstrous fusion of the divine and the profane. The bloated, corrupted form of his original Death Guard Terminator armor was still visible, stretched and fused with his daemonic flesh. His skin was the color of a fresh bruise, covered in weeping sores and boils that were lovingly tended to by giggling Nurglings that crawled all over him. In one hand, he held a colossal, pitted Manreaper scythe that dripped with a liquid that was every disease in the galaxy at once. His face was that of a fallen demigod, intelligent, ancient, and filled with a serene, fatherly malice.
He was not roaring or shrieking. He was humming a pleasant, discordant tune as he stirred a great cauldron of filth beside his throne with a ladle made from a human femur.
He looked up as they entered, his gaze passing over the Astartes as if they were insects, before settling on Rimuru. A slow, wet, and utterly terrifying smile spread across his face. His voice boomed in their minds, no longer a whisper, but the voice of the cathedral itself.
"Welcome, children," Vorlag the Vile said, his tone one of paternal warmth. "You have arrived just in time. The Grandfather's newest creation, a lovely little pox I call the Weeping Blossom, is almost ready to be shared."
He gestured to the cauldron, then to them. "And you… you shall be the first to hear its beautiful, blooming chorus."