The heavy iron gate slammed shut behind them, sealing the three fugitives in the dark.
The silence that followed was heavy, broken only by the wet, rhythmic sound of dripping sludge. Nyx raised Requiem. The hungry, dark-gold light of the blade pushed back the shadows, revealing a tunnel that was not made of stone, but of dead, gray wood.
"The air," Lyra whispered, her voice trembling. She held her wand up, casting a small bubble of clean air around their heads. "The toxicity levels are fatal. If we didn't have mana shielding, our lungs would be liquefying right now."
Briar adjusted her grip on Ignis. Her face was pale, illuminated by the flames of her sword. "It smells like the sewers back in the Capital. But... older. Sweeter."
"It smells like a corpse that refuses to rot," Nyx corrected.
He walked forward. The floor of the tunnel was spongy. It was the root of Yggdrasil, but it didn't feel like wood. It felt like diseased flesh. Black veins pulsed beneath their feet, carrying the toxic byproduct of the Seed deeper into the earth.
"Stay close," Nyx commanded. "The Second Shackle is screaming. Whatever is down here... it is wrong. It violates the laws of this universe...I think"
They walked for what felt like hours. The tunnel twisted and turned, sloping downward at a steep angle. The deeper they went, the hotter it became. It wasn't a natural heat, it was a fever heat. The World Tree was burning from the inside out.
"Look," Lyra pointed to the walls.
Embedded in the gray wood were weapons. Rusted swords. Broken spears. Shattered shields bearing the crest of the Elven Royal Guard.
"The expedition," Briar murmured, stopping to look at a helm that was half-swallowed by the bark. "Fifty years ago. King Aerion's father and his elite knights."
"They fought here," Nyx observed, looking at the deep gouges in the wood. "But there are no bodies."
"Maybe they retreated?" Briar suggested hopefully.
"No," Nyx said suddenly sensing something down the tunnel. He pointed Requiem further down the tunnel. "They are still here."
Ahead of them, the tunnel opened up into a large, spherical chamber. It was a hollow knot in the root system.
And standing in the center of the chamber were twelve figures.
They stood in formation, forming a defensive ring around the exit to the next level. They wore the armor of the Elven Royal Guard, beautiful, intricate plate mail made of moon-silver and white wood. But the armor was tarnished, black oil leaking from the joints.
"Elves?" Briar called out, stepping forward. "We are friends! We are here with King Aerion's blessing!"
The figures didn't move. They didn't breathe.
"Briar, wait," Lyra hissed, grabbing her cousin's cloak. "Look at their feet."
Briar looked down.
The knights didn't have feet.
Their greaves had melted. Their legs were fused into the floor of the chamber. Roots, gray, writhing roots, grew out of their armor, connecting them directly to the diseased tree.
They weren't guarding the tunnel. They were part of it.
"By the stars," Lyra gagged, covering her mouth.
"They aren't dead," Nyx said, his voice devoid of emotion, though his eyes burned with a cold fury. "The Seed... it didn't kill them. It repurposed them. It used their bodies as batteries to process the mana."
Creak.
The sound echoed through the chamber.
The central figure, the one wearing a rusted crown on his helm, twitched.
"Invaders..." a voice rasped. It didn't come from a throat. It came from the wood itself, vibrating through the armor.
The crowned figure lifted its head. The visor was open. Inside, there was no face. Only a swirling mass of black vines and glowing yellow eyes.
"Former Elf King?" Briar whispered, horrified.
"That is the former King," Nyx confirmed. "Or what is left of him."
The King raised a massive greatsword. It was fused to his gauntlet.
"Protect... the Seed," the King groaned. "Serve... the Masters."
"They are mind-controlled," Lyra analyzed, her hands shaking as she opened her grimoire. "The parasite has rewritten their neural pathways. They think they are protecting the Tree."
"Can we save them?" Briar asked desperately. "Nyx, you control plants! Can you separate them?"
Nyx looked at the twelve knights. He looked at the roots digging into their spines, pumping black sludge into their veins.
"No," Nyx said softly. "There is nothing left to save, Briar. Their souls were digested decades ago. These are just husks."
The King roared, a sound of tortured wood snapping.
"KILL!"
The twelve Hollow Knights moved.
They didn't charge, as they were rooted to the floor. Instead, the roots elongated. They lashed out like tentacles, allowing the knights to slide across the chamber with terrifying speed.
"Formation!" Briar screamed, suppressing her horror and letting her warrior instincts take over.
She leaped forward, Ignis blazing. She parried a strike from the King's greatsword.
CLANG.
The impact sent a shockwave through the room. Briar slid back, her boots carving grooves in the floor.
"He's heavy!" Briar shouted. "He hits like a golem!"
Two other knights lunged at Lyra, their spears darting forward like vipers.
"Shield!" Lyra chanted. A blue barrier erupted, deflecting the spears. But the black sludge dripping from the weapons hissed against her magic, eating through the shield like acid.
"My mana!" Lyra cried. "The sludge... it's draining my spell!"
"Don't let them touch you!" Nyx ordered.
He moved.
He didn't run. He flowed. The First Shackle flooded his limbs with power. He stepped inside the guard of a knight wielding a dual-axe.
The axe swung for his neck. Nyx caught the haft with his bare hand.
Hungry.
The Void flared.
Nyx didn't just stop the weapon; he drained it. The black sludge covering the axe was sucked into his palm. The knight shrieked, a sound of mechanical feedback.
Nyx drove Requiem into the knight's chest plate.
The black blade didn't meet resistance. It phased through the metal and the wood.
"Release," Nyx whispered.
The golden crack in his sword flashed. He didn't eat the knight. He severed the connection. He cut the invisible line tying the husk to the Rot.
The knight collapsed instantly, turning into a pile of dry dust and empty armor.
"They are connected to the floor!" Nyx shouted. "Cut the roots!"
"Got it!" Briar yelled.
She ducked under the King's swing. Instead of aiming for his head, she spun low, sweeping Ignis across the floor.
The fire-blade sliced through the thick gray roots tethering the King.
The King howled. He stumbled, his connection to the power source severed. But he didn't fall. The Rot inside him was strong enough to keep him moving for a few more seconds.
He raised his sword for a killing blow on Briar, who was still recovering from her spin.
"Briar!" Lyra screamed, firing a bolt of kinetic force that knocked the King's aim slightly off-center.
The greatsword smashed into the floor inches from Briar's head.
Nyx was there in a heartbeat.
He vaulted over Briar, bringing Requiem down in a vertical arc.
CRACK.
He cleaved the King's sword in half. He cleaved the King's helm in half.
He sliced straight through the armor, down to the ground.
The King froze. The yellow light in his visor flickered and died.
"Thank... you..." a faint, ghostly whisper echoed in the room.
The armor collapsed, empty.
Silence fell over the chamber. The other knights, sensing the death of their leader and the presence of a superior predator, recoiled. They dragged themselves back toward the walls, merging with the wood, becoming dormant again.
Briar sat on the floor, breathing heavily. She stared at the pile of armor that used to be the Elven King.
"That was..." Briar swallowed hard. "That was Aerion's father."
"He is at peace now," Nyx said, wiping black sludge from his blade. He offered a hand to Briar.
Briar took it. Her hand was trembling, but her grip was strong.
"How much deeper?" Briar asked, standing up.
"The resonance is stronger here," Nyx said, looking at the tunnel behind the dead King. "We are close to the Seed."
Lyra walked over to the pile of dust. She picked up the rusted crown.
"I will take this," Lyra said quietly. "For Aerion."
Nyx nodded. He looked at the tunnel ahead. The air coming from it wasn't just toxic, it was humming. It was a mechanical, rhythmic sound.
Thrum...Thrum...Thrum...
It sounded like a machine. Or a heartbeat.
"The Rot isn't just a fungus," Nyx said, his golden eyes narrowing. "It's a biological weapon. Be ready. What comes next won't be an Elf."
He walked toward the tunnel.
As he crossed the threshold, the Second Shackle slammed against his ribs. It wasn't pain. It was a memory.
He remembered this hum.
He remembered the abyss. He remembered twelve faces smiling at him. He remembered a machine exactly like this one being placed on his chest to drain his light.
Nyx's face went cold. The "Charm" and the softness of the previous night vanished. The God was back.
"Let's go," Nyx said, his voice vibrating with a terrifying power. "I want to break this thing."
They descended further.
The wood disappeared entirely. The walls of the tunnel were now made of a fleshy, biomechanical substance, gray matter pulsing with neon-blue veins.
They reached the final chamber. The Heart Root.
It was a cavern so large the ceiling was lost in shadow. In the center, suspended over a pit of infinite darkness, was the Heart of Yggdrasil.
It should have been a massive, glowing knot of golden wood.
Instead, it was encased in a machine.
A massive, geometric structure made of white metal and black glass was clamped around the Heart. Needles the size of telephone poles were driven into the wood, pumping a glowing blue liquid out of the tree and into a series of pipes that vanished into the ground, heading toward the center of the continent.
And guarding the machine was a monster.
It wasn't an animal. It was a conglomeration of corpses. Hundreds of Elves, beasts, and monsters had been fused together by the Rot into a towering, multi-limbed abomination. It had no head, only a massive, vertical mouth filled with rotating saws.
"The Guardian," Lyra whispered, her face draining of blood. "That... that thing is made of the missing expedition."
The Guardian sensed them. It turned its bulk slowly. A dozen eyes opened on its torso.
It let out a scream that sounded like twisting metal.
Nyx stepped forward. He felt the hunger of the Void rise up, matched only by his rage.
"Briar, take the left," Nyx commanded. "Lyra, target the joints. I will take the mouth."
He pointed Requiem at the machine behind the monster.
"We kill the guard. We smash the machine. We save the world tree"
The Guardian charged.