The dungeon air smelled like rust and death.
Cold. Wet. Heavy.
Every breath burned Kai's lungs as if the darkness itself was choking him. The walls around the team pulsed faintly, veins of crimson light crawling across the stone like something alive. Drops of black liquid fell from the ceiling, each impact echoing too loudly in the suffocating silence.
This place was wrong.
Even for a dungeon.
"Kai, hurry up!" someone shouted from the front.
He flinched.
"Y-Yeah… I'm coming."
His voice trembled. It always did.
Kai tightened his grip on the cheap dagger in his hand. His fingers were shaking so badly he almost dropped it. He hated this. He hated the fear. He hated how useless he felt.
But most of all… he hated himself.
Behind him, a monster's corpse lay twisted, its body half-melted by magic. The others had killed it easily. As always, he had only watched.
Again.
Useless.
The word had followed him his entire life.
He forced his legs to move.
Ahead, the group stood in front of a massive door covered in ancient symbols. Crimson light leaked from the cracks.
This was the deepest part of the dungeon.
Rank S.
They had no business being here.
And yet, the guild had sent them.
Or rather… they had volunteered.
For glory.
For promotion.
For money.
For fame.
Kai had only come because they asked him.
Because they were his friends.
Because he thought… maybe this time, he could be useful.
The leader, Jae-min, turned around. His confident smile was gone. His eyes were cold.
"We found it."
Kai blinked. "Found… what?"
"The hidden chamber."
The others looked excited. Greedy.
Something twisted in Kai's stomach.
The girl beside Jae-min stepped forward.
Lina.
The person he trusted most.
The only one who had always been kind to him.
Her soft smile was gone too.
"Kai," she said gently, "come here."
He walked toward them.
His heart was beating too fast.
Too loud.
Too wrong.
"What's inside?" he asked.
Jae-min placed his hand on the door. "A relic. Something powerful."
"And?"
"And… there's a condition."
Kai froze.
"What condition?"
Silence.
No one answered.
The dungeon seemed to grow colder.
Jae-min spoke again, voice calm.
"The door requires a sacrifice."
Kai laughed nervously. "A monster, right? We killed plenty."
"No."
The word cut through the air.
"A human."
The world stopped.
Kai's brain refused to understand.
"…What?"
Lina looked at him.
For a second, he saw hesitation.
Then it vanished.
"We discussed it already."
His vision blurred.
"What… do you mean?"
Jae-min stepped closer.
"You know what we mean."
Kai took a step back.
"No… wait… there must be another way—"
"There isn't."
"I can help! I'll do anything! I'll train more! I'll—"
"You are weak."
The words hit harder than any blade.
"You slow us down."
"I—"
"You're Rank F. You have no ability."
"I can still—"
"You've always been a burden."
Something inside Kai cracked.
He looked at Lina.
She avoided his eyes.
"…Lina?"
Her lips trembled.
"I'm sorry."
His chest tightened.
"You said… we were friends."
"We are."
"Then why?"
Tears formed in her eyes.
"Because I want to live."
The sentence destroyed him.
Jae-min grabbed Kai's collar.
"It's nothing personal."
The others surrounded him.
Their faces were empty.
Strangers.
Monsters.
"Wait—please—"
They pushed him toward the door.
"No! STOP!"
He struggled.
Panicked.
Screamed.
No one listened.
The door opened.
Darkness.
A bottomless abyss.
Something moved inside.
Something huge.
Something hungry.
Kai clawed at the ground.
"PLEASE!!"
Lina whispered, "I'm sorry."
And pushed him.
He fell.
The world turned upside down.
The last thing he saw was their silhouettes… shrinking… disappearing.
The door closed.
Darkness swallowed everything.
He hit the ground.
Pain exploded through his body.
Bones cracked.
Air left his lungs.
He couldn't breathe.
He couldn't move.
Something wet touched his face.
Blood.
His blood.
Footsteps echoed.
Slow.
Heavy.
He forced his eyes open.
A creature stood before him.
Tall.
Deformed.
Its body stitched together from multiple monsters. Eyes growing from its skin. Mouths opening and closing, whispering in broken voices.
An experiment.
Horror crawled under his skin.
He tried to move.
His body didn't respond.
The creature leaned closer.
It smelled him.
"Fresh…"
Kai cried.
"Please… don't…"
It raised its arm.
Death.
Then—
A voice.
Inside his head.
Cold.
Mechanical.
[Compatibility confirmed.]
[Experimental Subject: 000.]
[Abyss Integration System activating.]
His vision filled with light.
The monster froze.
Time stopped.
Kai's eyes widened.
"What… is this…?"
[You have been selected.]
[Do you accept evolution?]
[YES / NO]
He laughed weakly.
"…What kind of question is that…?"
Tears streamed down his face.
"They betrayed me…"
His voice broke.
"I don't want to die."
His expression twisted.
"I want… power."
The screen glowed.
[YES selected.]
Pain.
Unimaginable.
His body convulsed.
Bones shattered and reformed.
Veins turned black.
His scream echoed through the abyss.
The creature stepped back.
Fear.
For the first time.
Fear.
Kai's mind fractured.
Memories burned.
His emotions drowned.
Something cold replaced them.
The voice returned.
[Welcome, User.]
[You are now the host of the Abyss.]
Kai's eyes opened.
No fear.
No hesitation.
Only silence.
Only calculation.
Only hunger.
He looked at the monster.
And smiled.
"Let's begin."
The creature hesitated.
That alone was unnatural.
Monsters in dungeons did not hesitate. They did not feel fear. They did not think. They killed.
But now it stood there, twitching, its many eyes focusing on Kai as if trying to understand what had changed.
Kai slowly pushed himself up from the ground.
Every movement felt… different.
His body was lighter. Stronger. More precise. The pain was still there, but it had become distant, like an old memory.
He flexed his fingers.
They no longer trembled.
A dark notification appeared in his vision.
[Basic Integration Complete.]
[New Skills Acquired.]
[Abyssal Instinct – Lv.1]
[Predator's Focus – Lv.1]
Information flooded his mind.
Angles. Distances. Weak points.
The world turned into data.
Kai tilted his head.
"So this is… power."
The monster roared and lunged.
Fast.
Much faster than before.
Before, Kai would have died instantly.
Now—
Time slowed.
No.
His perception accelerated.
He stepped to the side.
Effortless.
The creature's claws tore the ground where he had been.
Kai observed calmly.
Its joints were unstable. The stitches connecting its limbs were weak. Its core pulsed beneath the ribcage.
"Too many flaws."
He moved.
One step.
Two.
He grabbed a broken bone from the ground.
Improvised weapon.
The monster turned.
Too late.
Kai drove the bone into the glowing core.
The creature screamed.
Dozens of mouths howled.
Black blood exploded.
But Kai didn't stop.
He twisted the weapon deeper.
"Die."
The light in the monster's body flickered.
Then vanished.
Silence.
For a moment, nothing happened.
Then—
The corpse began to melt.
Black smoke rose and flowed toward Kai.
He frowned.
"What—"
The smoke entered his body.
Pain surged again.
But this time… it was intoxicating.
Power filled his veins.
The system spoke.
[Target absorbed.]
[Ability acquired: Regeneration – Lv.1]
[Stats increased.]
Kai exhaled slowly.
He could feel it.
His wounds were closing.
His broken bones knitting together.
He looked at his hands.
"…So I devour them."
A smile slowly spread across his face.
"Good."
He turned.
The abyss was vast.
The chamber stretched endlessly into darkness.
Shapes moved in the distance.
More monsters.
More power.
More evolution.
His eyes gleamed.
But then—
A sound.
Clap.
Clap.
Clap.
Kai froze.
Someone was there.
A woman stood atop a broken pillar.
Long dark hair.
Pale skin.
Eyes like endless night.
She wore no hunter uniform. No armor. No fear.
Only amusement.
"I was wondering," she said softly, "how long it would take."
Kai stared at her.
"Who are you?"
She tilted her head.
"Your future."
The air grew heavy.
His instincts screamed.
Danger.
Extreme danger.
The system reacted.
[Warning.]
[Unknown Entity detected.]
The woman jumped down gracefully.
She walked toward him as if the abyss belonged to her.
"Tell me," she whispered, stopping only a few steps away, "how does it feel?"
Kai's gaze sharpened.
"What?"
"To become something… inhuman."
Silence stretched.
Then Kai answered calmly.
"…Refreshing."
Her smile widened.
"Good."
For a brief moment, her eyes glowed.
Monstrous.
Beautiful.
Terrifying.
"I've been waiting a long time," she said.
"For someone like you."
Kai narrowed his eyes.
"And why is that?"
She leaned closer.
"So I won't be alone anymore."
Before he could react—
She touched his chest.
A surge of darkness exploded.
Visions flooded his mind.
Experiments.
Screaming subjects.
Scientists.
Broken bodies.
A laboratory.
A child.
Him.
Kai staggered.
"What… is this…?"
She stepped back.
"Memories."
His breathing became uneven.
"You…"
Her voice turned gentle.
"I am the Guardian of the Abyss."
The world seemed to tilt.
"And you…"
She smiled.
"…are its new master."