The tunnel narrowed to a choking throat of concrete and black water as Raon and Han sprinted through the left passage. Water splashed violently against their waists; the darkness gnawed at their ankles with every step.
Behind them, the swarm came.
Skittering. Clicking. Grinding mandibles scraping the walls.
Monsters poured into the tunnel like a flood of living shadows.
"Faster!" Han shouted, panting, swinging his sword behind him. The blade scraped across a creature's skull, sparks bouncing off the wet walls.
"They're almost—"
Something moved beneath the water.
Raon felt it—a vibration, a tremor—one heartbeat before it struck.
A pale arm shot out of the black water and clamped around Han's ankle.
"AH—!"
Han lost his footing and slammed into the filthy water, immediately being dragged backward.
More pale arms surfaced. Half-rotted. Human-shaped, but wrong. Their joints bent the wrong way.
Han slashed desperately at the arms, but each cut only made more hands rise from beneath.
"Raon! Help—!"
His fingers clawed at the water's surface as the creatures pulled him under.
Raon didn't think.
He plunged toward him, sword flashing.
SHIKK—!
The blade severed the first arm. Then the next. Black water frothed with rotten flesh and the howl of inhuman jaws snapping below.
But the swarm was closing in.
Hundreds of centipede-like monsters crawled along the walls, the ceiling, the water.
Their mandibles clicked in hunger.
Raon's pupils trembled.
He reached into his bag and grabbed the white orb.
"Han," he said quietly, "close your eyes. Cover your ears."
"What—?"
"Do it!"
The monsters lunged.
Raon threw the orb.
FSSSHHH—!
The world exploded.
A sun bloomed inside the tunnel.
White light burst like a supernova, reflecting off the water, ripping through every shadow. Even Raon felt it scorch through his eyelids.
The swarm shrieked. A single, unified scream of pain and confusion.
Raon grabbed Han's collar.
"Move!"
Blinded monsters writhed behind them as the two plunged deeper into the sewer's black throat.
They didn't stop running until the water thinned and a faint glow appeared ahead.
"…Light?" Han whispered.
They stepped into an enormous underground chamber.
A broken waste-control tank, hollow and cavernous, like the stomach of some dead giant.
Concrete walls stretched high above them, slick with condensation.
At the very top—
A round metal manhole cover.
The faint glow of the outside world leaked through its rusted edges.
"We can climb that," Han said breathlessly. "We can get out of here."
Raon stared up the impossibly tall walls.
The manhole was at least twenty meters above them—straight vertical.
"We'd need a rope… or a skill… or—"
A sound cut him off.
…chrrrrrrr—…chrrrk…
It came from behind.
The tunnel they emerged from began to vibrate.
Han's face paled.
"They're coming."
Dozens of smaller monsters spilled into the tank entrance.
But they didn't advance.
They stopped.
Frozen.
Something else was coming.
Raon felt it before he saw it.
The air changed.
The water trembled.
Even the dead things rotting in the corners seemed to recoil.
Then—
KRSHHHHHHH—!!
The ceiling above them split open.
A colossal jaw, armored in black chitin, ripped through the concrete like tissue.
Hundreds of legs clattered across the shattered ceiling.
A body like a living train slithered downward, each segment rippling with oily reflections.
A centipede longer than a bus.
A predator that ruled the dark.
The Abyssal River Centipede descended into the tank.
Its mandibles seized three smaller monsters at once and crushed them with a wet crack.
Han's breath stopped.
"…That… thing…"
Raon didn't move.
He couldn't.
Fear pressed against his ribs like a knife.
The smaller monsters, terrified, retreated from the tank entirely, refusing to step inside.
The tank was no longer a battlefield.
It was a feeding ground.
For the creature above.
KRRRR-CHHH—
The centipede's head snapped toward Raon and Han.
The tunnel behind them collapsed with a thunderous roar.
Their escape route was buried under tons of concrete and mud.
Only one exit remained:
The manhole above.
Twenty meters straight up.
No ladder.
No rope.
No footing.
And below them—
Death with a thousand legs.
Raon exhaled slowly.
"…We're trapped."
Han tightened his grip on his sword, knuckles white.
"What do we do now?"
Raon looked up at the manhole.
Then down at the monster.
Then at the trembling water around its massive body.
His voice came out steady.
"…We survive."
And the centipede roared.
The moment the tunnel collapsed, dust and concrete rained down like a dying city's ashes.
Raon and Han shielded their faces, coughing inside the vast water tank chamber.
The only exit—the manhole far above—was unreachable without equipment.
And below them…
The giant centipede monster uncoiled.
Its armored segments scraped the concrete with metallic screeches. Its mandibles clicked together like two blades eagerly sharpening for flesh.
Han whispered, voice trembling,
"W-We're trapped… Raon, we're completely trapped."
Raon didn't answer.
His eyes were fixed on the monster.
Then—
A blue window snapped into existence in front of both of them.
[Hidden Quest Discovered]
Objective: Eliminate the mutant Centipede (Lv. 30)
Rewards:50,000 Coins
Hidden Achievement: "Golden Monkey Eye (Artifact – Grade-?)"
Failure: Death.
Han stared, horrified.
"A hidden quest? Now?!"
Raon clenched his fists instantly.
Han hissed, "ARE YOU INSANE?!"
Raon didn't blink.
"Han… if we don't kill it—"
He pointed behind them.
"—we're not getting out," Raon finished.
The centipede lunged.
Raon shoved Han aside as the jaws snapped down where they stood.
CRUNCH!
Concrete shattered under the monster's bite.
Han scrambled up, swinging his sword wildly.
Raon shouted, "ITS SOFT SPOT IS UNDER THE SEGMENTS! AIM FOR THE GAPS!"
Han slashed at the exposed membrane between two plates—
SPURT!
Black blood sprayed.
The centipede screeched—a noise that rattled Raon's skull. The entire tank vibrated like something alive and furious.
"Nice job!" Raon yelled.
But the monster moved impossibly fast.
WHIP!
Its tail struck the ground, sending cracks spiderwebbing through the concrete as shockwaves knocked both men back.
Han rolled, coughing. "It's too strong!"
Raon pulled out another orb—smaller, glowing faintly.
Han's eyes widened. "WAIT, THAT'S—"
"I know. Cover your eyes!"
Raon hurled it.
BOOM—!
A burst of blinding white light exploded outward like the birth of a small sun.
The monster screeched, thrashing wildly, smashing pillars and spraying black ichor across the walls.
Han used the moment of blindness to sprint forward and stab into a joint—
KSHHHK!
Another piece of armor split open.
They were hurting it—but not nearly enough.
The centipede reared upward, clinging to the wall like some nightmarish serpent god, its countless legs piercing the concrete.
Raon felt a chill crawl up his spine.
It's adapting.
The creature's mandibles opened wide.
Energy gathered inside its throat—
—a faint glow, unnatural for any sewer creature.
Raon's eyes widened.
"HAN! MOVE—!"
FWOOOOSH!
A torrent of pressurized black liquid blasted from its mouth. Acid? Venom?
The ground sizzled where it hit.
Han jumped aside, barely.
Raon didn't have the same luck.
He felt the spray graze his shoulder—burning, like a dozen hot needles stabbing into his skin.
He gritted his teeth and forced himself to stand.
The centipede lunged downward.
Raon raised his sword—
But he knew.
It was too fast.
CRACK—!!!
The monster's head slammed into Raon's chest like a battering ram.
His body flew across the tank and smashed into the wall.
Air exploded from his lungs.
His vision blurred.
His fingers numbed.
The system windows flickered in and out as his consciousness slipped.
The last thing he heard was Han screaming his name—
RAON!!"—and then everything went black.