85

Chapter 85 — The Depths Below

The staircase continued far deeper than Subin had expected. It was wide enough for the entire expedition to descend without difficulty, but its construction was unlike anything they had encountered elsewhere in Blackstone Dungeon. The steps were carved from a single dark material that absorbed most of the light around it, and thin blue lines ran along the edges of each step, carrying mana downward. There were no crystals growing from the walls, no roots breaking through the stone, and no signs of ordinary life. The deeper they descended, the more isolated the upper ecosystem felt.

After nearly fifteen minutes, Yerin finally checked the expedition instruments again. "We've descended at least two kilometers."

"Only two?" Min-seok asked.

"According to the pressure readings."

Subin glanced at the walls. "The actual distance may be greater."

Jae-hyun looked at him. "How?"

"The space is compressed."

He stopped beside one of the walls and placed his hand against it. The stone felt solid, but his perception detected something unusual beneath its surface. Mana wasn't simply flowing through the dungeon. The space itself was being affected by the concentration of mana.

"Blackstone Dungeon isn't completely normal anymore," Subin said. "The deeper regions have enough mana to distort the environment."

Yerin looked concerned. "Could that affect our return?"

"Possibly. That's why we shouldn't separate."

Nobody argued.

They continued as a group.

The staircase eventually widened into a huge circular chamber.

There were no monsters.

Instead, hundreds of small black stones floated several meters above the floor.

Each stone was connected to the others by thin strands of blue mana.

The entire chamber looked like a three-dimensional network.

Subin immediately understood what he was seeing.

"A map."

Yerin stared at the floating stones.

"A map of what?"

"The dungeon."

Subin walked toward the center.

The stones shifted as he approached, revealing different layers of the underground environment. The upper forest, the Mana Tree, the elemental platform, the black lake, and numerous other territories appeared as connected points.

But what caught Subin's attention was the bottom.

The map extended much farther downward than their current position.

Several regions were completely dark.

They weren't unexplored in the sense that humans had never entered them.

The dungeon itself simply had no information available.

Then one section illuminated.

[Current Location.]

Another point appeared directly beneath it.

[Deep Mana Reservoir.]

And below that was a much larger region.

[Core Territory.]

Subin's expression became serious.

Yerin approached.

"Is that the deepest point?"

"Not necessarily."

The map changed.

The Core Territory wasn't the end.

It was merely the largest known concentration of mana.

Below it was an area marked only by a single symbol.

No name.

No rank.

No estimated level.

Subin looked at it for several seconds.

"What is that?" Yerin asked.

"I don't know."

He wasn't particularly bothered by the lack of information.

The important thing was that the dungeon had a structure.

The mana conduits carried energy downward. The forests processed it. The elemental platform concentrated it. The deeper reservoir stored it. Everything eventually moved toward the Core Territory.

But why?

Subin stepped closer to the map.

The black stones rearranged themselves.

A faint line appeared between the Core Territory and the unknown region.

Mana was flowing through it.

Subin's eyes narrowed.

"The core isn't the source."

Jae-hyun understood immediately.

"It's receiving mana?"

"Yes."

That changed the meaning of the dungeon completely.

The massive Mana Tree wasn't generating the dungeon's power.

The elemental platform wasn't generating it.

The Core Territory wasn't generating it either.

All of them were components of a larger circulation system.

Something else was providing the original energy.

Or perhaps the dungeon had been collecting it for a very long time.

Subin stepped away from the map.

"We continue."

The expedition crossed the chamber and entered another passage.

This one was much narrower.

After several hundred meters, they began encountering monsters.

The first was a dark-skinned humanoid creature carrying a massive stone weapon.

[Deepstone Warrior]

Level: 107

Rank: A+

It stood motionless in the middle of the passage.

The moment the expedition entered its territory, it raised its weapon.

Subin stepped forward.

"I'll handle it."

The creature charged.

Unlike Kael or the Convergence Beast, it possessed no sophisticated adaptability. Its strength came from physical reinforcement and extremely dense mana.

Its first swing created a pressure wave that cracked the walls.

Subin shifted to the side and allowed the weapon to pass.

The warrior immediately recovered and attacked again.

This time Subin met the weapon directly.

The impact pushed both of them backward.

Subin's feet left shallow marks across the stone.

The warrior's strength was considerable.

But its movements were predictable.

Subin didn't need a complicated strategy.

He allowed the creature to establish its rhythm, then interrupted the connection between its attacks.

Simple Edge slipped beneath the stone weapon and struck the creature's wrist.

The warrior immediately changed its grip.

Subin followed the transition.

A second cut struck its shoulder.

The creature staggered.

Subin stepped inside its range and delivered one final strike across its chest.

The Deepstone Warrior collapsed.

[Deepstone Warrior defeated.]

[Level 107 A+ monster eliminated.]

A dense mana core rolled across the floor.

[Deepstone Core obtained.]

Subin stored it.

There was no dramatic feeling of victory.

The creature had simply been another obstacle.

The expedition continued.

Over the next hour, they encountered several more monsters.

A Level 110 A+ centipede with crystal armor.

A Level 113 A+ bird that attacked from the ceiling.

A Level 108 A+ bear that could harden its body until it resembled black metal.

None possessed the refinement of Kael.

None required Subin to reveal a completely new technique.

But every battle taught him something.

The deeper territory had a different style of strength.

The monsters weren't individually more complicated.

They were simply more efficient.

Their mana density was extremely high, and their bodies had adapted to survive under constant pressure.

Subin's Sword Intent gradually became sharper.

[Sword Intent: 91.4% → 92.1%.]

He didn't notice the notification immediately.

His attention was focused on the environment.

The passage eventually ended at another enormous chamber.

This one contained water.

A vast underground sea stretched beyond the expedition's lights.

The surface was completely black.

Unlike the earlier Blackwater Lake, this sea was far larger.

There was no visible opposite shore.

Yerin stared at it.

"There's no way this is still inside the dungeon."

Subin looked upward.

"The ceiling is too far away."

A moment later, the system provided an answer.

[Subterranean Ocean detected.]

[Estimated area: Unknown.]

[Depth: Unknown.]

[Mana Density: 487%.]

Everyone became silent.

Nearly five times the environmental mana density of normal conditions.

Even the strongest expedition members felt pressure on their bodies.

Subin walked to the edge.

Something moved beneath the surface.

Then another.

Then dozens.

The sea was filled with life.

Large silhouettes moved through the darkness, some hundreds of meters long.

The expedition members instinctively prepared their weapons.

Subin raised his hand.

"Don't attack."

Yerin looked at him.

"There's something bigger than the monsters we've fought."

"Yes."

He could feel it.

Not one creature.

An ecosystem.

The sea was home to countless powerful beings, and most of them had no interest in the expedition.

They were simply living in their own territory.

Subin watched a massive serpentine creature swim beneath the surface.

Its body was longer than several buildings.

The system briefly scanned it.

[Abyssal Sea Serpent]

Level: 119

Rank: A+

The creature continued moving.

Then a second shadow passed underneath it.

Larger.

Much larger.

The system couldn't identify it.

[Target outside current identification parameters.]

Subin's eyes narrowed.

But he didn't pursue it.

There was no reason to enter an unknown ecosystem without preparation.

Instead, he looked along the coastline.

A narrow crystal bridge extended across part of the sea.

It appeared to lead toward the other side.

"That's our route."

Yerin looked at the bridge.

"You're sure?"

"No."

She sighed.

Subin smiled slightly. "But it's the only visible route."

The expedition carefully stepped onto the bridge.

It was surprisingly stable.

The crystal beneath their feet wasn't fragile like the formations above. It was extremely dense and seemed to absorb the pressure from the sea below.

Halfway across, the water suddenly became violent.

A massive creature surfaced.

It resembled a crocodile with six eyes and a long armored body.

[Abyssal Devourer]

Level: 121

Rank: A+

It opened its mouth.

The mana pressure alone pushed several expedition members backward.

Subin stepped forward.

The creature lunged.

Subin didn't retreat.

Simple Edge moved once.

The blade passed through the space between the creature's jaws.

A thin line appeared across its neck.

The creature continued moving for another few meters before collapsing into the sea.

A huge wave struck the crystal bridge.

The expedition held its position until the water settled.

Subin looked down.

The Devourer's body sank into the darkness.

Something beneath the sea immediately approached it.

The body disappeared.

Subin's expression remained unchanged.

"Keep moving."

They crossed the remaining distance.

On the other side of the ocean was a massive stone gate.

This gate was unlike the structures above.

It wasn't connected to mana conduits.

It wasn't part of the dungeon's ecosystem.

It looked like a boundary.

Subin approached.

A system notification appeared.

[Core Territory Entrance detected.]

[Recommended Rank: A+]

[Minimum Level: 110.]

[Current Expedition Capability: Marginal.]

Yerin read the message and frowned.

"Marginal?"

Subin nodded.

"It means we're strong enough to enter."

"And?"

"Not necessarily strong enough to stay."

Nobody spoke for a moment.

Subin looked at the expedition.

They had come this far together.

The deeper region would become increasingly dangerous, and unlike the upper territories, the monsters here were already beyond the level of ordinary A-rank expeditions.

"We'll enter carefully," Subin said. "If the environment becomes too dangerous, we return."

Yerin nodded.

The others agreed.

Subin placed his hand against the gate.

It opened.

A wave of mana emerged.

For the first time since entering Blackstone Dungeon, Subin felt genuine pressure from the environment itself.

Not killing intent.

Not hostility.

Simply overwhelming density.

The corridor beyond was enormous.

Black stone walls stretched into the distance, covered with countless blue veins.

At the end of the corridor was a faint light.

Subin stepped inside.

The system immediately updated.

[Core Territory entered.]

[Blackstone Dungeon Exploration Progress: 42% → 46%.]

[Environmental Mana Density: 563%.]

[Estimated Monster Level: 115–140.]

[Confirmed Rank: A+.]

Subin's grip tightened around Simple Edge.

He could feel something different here.

The dungeon's mana wasn't merely circulating.

It was concentrating.

And the farther they walked, the more clearly Subin could sense a massive presence beneath the floor.

Not necessarily a monster.

Not necessarily an enemy.

Something that had been at the center of this ecosystem long before humans discovered the dungeon.

The expedition continued into the Core Territory.

Behind them, the enormous stone gate slowly closed.

Ahead, the path descended once again.

And this time, there was no map showing how far it went.