The thing hit the wall and kept moving.
Stone screamed.
Dust punched through the air and hit Jaehyuk's tongue, dry and bitter.
He ducked under a swinging arm made of black metal and grabbed the chain wrapped around it.
The chain was hot.
Not warm. Hot enough to sting through his palm.
"Left!" Mira snapped.
Jaehyuk moved left.
A second thing dropped from the ceiling and slammed into the floor where his skull had been a breath earlier.
The impact shook his knees.
The floor under them wasn't rock anymore.
It was grating.
Industrial mesh laid over something hollow.
Somin coughed and coughed, the sound thin in the metallic corridor.
"I hate this floor," she said.
"We're not on a floor," Mira said.
She hacked down at the thing in front of her.
Her blade rang against it.
Not flesh.
Not bone.
Steel.
The monster folded at the waist like a broken machine and whipped a tendril at her ankle.
Jaehyuk stamped on it.
It twitched.
Then went still.
He stared at it for half a second.
The body had no eyes.
No mouth.
Just a barrel-shaped core with four limbs, a rotating joint, and a brass plate sunk into its chest.
MAINTENANCE UNIT 83-B.
"That's not a monster," Somin said.
"Good," Jaehyuk said. "Because I was starting to get annoyed."
Another unit clanked around the corner.
Then another.
Then three more, moving in a line down the corridor like someone had set them loose from a factory.
They weren't hunting.
They were routing.
One turned its head and emitted a low chirp.
A thin door in the wall slid open three meters ahead.
A second door closed behind them.
Mira looked at Jaehyuk. "Explain."
"I don't know this floor," he said.
That made her stare harder.
It was true.
He knew the upper floors were strange. He knew the Tower got cruel above eighty. But this was different. This didn't feel like a trial wearing a skin.
It felt like the skin was the point.
Like the floor was a hallway built around something else.
Somin pressed a hand to her ribs and winced.
The air in here was wrong.
Too dry.
It scratched her throat.
And under it, a smell like oil and old electricity.
"I can hear water," she said.
Jaehyuk listened.
Faintly, behind the walls, something was moving.
Not water.
Fluid through pipes.
A hum.
Vibration.
He put his hand on the wall and felt it through the stone.
The Tower was ringing.
Not the floor.
The Tower itself.
"This is infrastructure," he said.
Mira's gaze flicked down the corridor. "For what?"
"Containment," he said.
The maintenance units clanked closer.
Their limbs unfolded in perfect sequence, like a drill they'd been given a thousand times.
Functions.
Not beasts.
Not spawns.
Functions.
One raised an arm.
A needle shot out.
Mira knocked it aside with the flat of her sword.
"Move," she said.
They ran.
Not because they had a route.
Because the corridor decided they needed one.
The walls kept changing.
Not visibly.
Subtly.
A door where there hadn't been one.
A vent that exhaled hot air on the left and cold on the right.
Floor panels that clicked under Jaehyuk's boots before settling back into silence.
He tasted metal on his lips.
Somin's breathing got worse with every turn.
"I need a second," she said.
"No," Mira said.
"My lungs are not a contract."
"They are right now."
Jaehyuk held up a hand and stopped them at a junction.
Three corridors.
Each marked with symbols.
Not runes.
Pictograms.
One showed a hand.
One showed a droplet.
One showed a skull crossed out.
He frowned.
It was a control map.
"That one," he said, pointing to the droplet.
Mira didn't ask why.
She just went.
The corridor narrowed and the air changed.
Humid.
Warm.
It smelled like rust and wet stone and something sweet rotting under it.
Somin gagged.
"Yeah," Jaehyuk said. "That's bad."
A metal grate overhead shuddered.
Something heavy shifted above them.
Then a voice came through the wall.
Flat.
Distorted.
"...containment breach... sector eight... reseal..."
Somin stopped walking.
Mira stopped with her.
Jaehyuk looked up.
"Did that just talk?"
"Yes," he said.
"Like a person?"
"No. Like a system."
He'd heard that voice before.
Not here.
Not this exact tone.
On lower floors, through hidden channels. On the archive logs. On contract notices that sounded too clean.
The Tower had a bureaucracy voice.
He had hated it then.
He hated it more now.
The corridor opened into a chamber so large Jaehyuk couldn't see the ceiling.
Rings of catwalks crisscrossed the space.
Below them, a basin the size of a stadium.
Inside the basin, thick glass tubes rose out of the floor in rows.
Most were empty.
Some had been shattered.
A few still held shapes.
Not monsters.
Not people.
Things suspended in grey fluid.
One opened a lidless eye when they entered.
Then blinked.
Somin stopped breathing for a full second.
"No," she whispered.
Mira moved in front of her without thinking.
Jaehyuk stared.
The thing in the tube was humanoid only in the broadest sense.
Too long in the limbs.
Skin like wet ash.
Needles threaded through its chest and spine.
A collar around its neck.
On the glass, a label.
FUNCTIONAL ENTITY 04.
Under it, smaller text.
LOWER FLOOR NAVIGATION. ACTIVE.
"Those are monsters," Somin said, voice shaking. "That's a monster."
"No," Jaehyuk said.
He hated how calm his own voice sounded.
"That's a tool."
The eye in the tube moved.
It tracked them.
Then the thing spoke.
Not with its mouth.
With a speaker somewhere in the collar.
"You should not be here."
Somin made a strangled sound.
Mira's sword came up.
Jaehyuk stared at the tube.
"You talk," he said.
"I am permitted speech when interfacing with authorized movement," the thing said.
Its voice was dry and thin, like paper dragged over wire.
"You are not authorized."
Mira's eyes narrowed.
"What are you?"
The thing twitched in the fluid.
The needles in its spine shifted with a wet clicking sound.
"A function," it said.
The words landed harder than a scream.
Somin looked from one tube to another.
There were more labels.
REPAIR.
FILTER.
REDIRECTION.
OBSERVATION.
It wasn't a prison.
It wasn't a nest.
It was a machine room with skin on it.
Jaehyuk felt something cold move under his ribs.
The Tower was not making monsters.
It was deploying processes.
"Who built this?" Mira asked.
The thing in the tube turned its eye toward her.
"The Tower is older than your guilds," it said.
"That wasn't the question," Jaehyuk said.
"It is the only question," the thing answered.
A bell sounded somewhere above them.
Deep.
Not loud.
Heavy enough to rattle their teeth.
The floor panels lit one by one in a path across the chamber.
Mira saw it first.
"Movement route," she said.
"For us or for it?" Somin asked.
The answer came before anyone could speak.
The catwalk under their feet trembled.
A panel opened.
Cold air rose from below.
And a new unit climbed up with a wet metal hiss.
This one was larger.
Better made.
Its chest plate bore a gold line through the center like a rank insignia.
A command unit.
It turned its head.
No face.
Just a speaker grille.
"Unauthorized climbers detected," it said.
"Climbers," Somin repeated.
Her voice cracked on the word.
The unit spread its arms.
From the ceiling, more doors began opening.
Not one.
Dozens.
The sound was everywhere.
Metal sliding.
Locks releasing.
Something was waking up.
Jaehyuk grabbed Somin's wrist.
"Can you run?"
She swallowed hard. "I can scream."
"Try running first."
Mira stepped forward.
"How many?"
Jaehyuk counted the doors.
The movement lines.
The basin below.
The tubes.
Too many.
"Enough to mean it," he said.
Mira gave him a sharp look. "That your version of panic?"
"My version of panic is quieter."
The command unit raised one hand.
The functional entity in the tube behind them started to thrash.
Its collar flashed red.
Then its speaker rasped, "Do not let them reach the upper levels."
Somin stared at it.
"What?"
The creature's eye rolled toward the ceiling.
Toward something above.
Not the chamber.
Above the Tower.
"The Tower is keeping something above," it said.
The words hit the air like a thrown knife.
Mira didn't blink.
Somin did.
Jaehyuk went still.
The functional entity twitched hard against its restraints.
Its voice dropped to a broken hiss.
"You don't understand what it is holding shut."
The command unit on the catwalk began to charge.
Its chest split open.
Light gathered inside.
Jaehyuk tasted ozone.
Mira swore.
Somin grabbed his sleeve so hard her nails bit through cloth.
Above them, the doors kept opening.
And the thing in the tube, the function, the prisoner, whatever it was, slammed one fist against the glass and shouted like it wanted the whole Tower to hear.
"If it opens, everything below dies first!"