169 - The Ruined City

The dark surface of the boundary rippled as Subin approached, but nothing emerged from the other side. The red glow beyond it remained steady, reflecting faintly across the underground chamber. Behind him, the Ancient Forest Guardian continued to stand at the top of the stairs, its enormous body partially hidden among the roots. It had not followed them into the chamber, and its presence made the situation strangely clear. The forest had brought them as far as its own territory allowed. Whatever existed beyond the boundary belonged to another environment.

Subin turned toward the others. “We don't know what is on the other side, so stay together. No unnecessary fighting, and don't cross the boundary until everyone is ready.”

Yerin adjusted her grip on her spear while Jae-hyun and Liu Wei moved closer to the center of the group. Ethan checked the mana sword forming along his hand, and Rafael secured the equipment strapped across his back. Ara prepared several independent recording devices in case the environment interfered with their primary equipment again.

Once everyone was ready, Subin stepped through.

The sensation lasted less than a second.

The humid forest air disappeared.

Dry heat struck his face.

His boots landed on hard stone.

Subin immediately noticed that the ground beneath him was no longer natural soil. Large slabs of cracked black stone stretched in every direction, partially buried beneath dust and sparse vegetation. Above them hung a dark sky filled with heavy clouds, while a distant crimson sun cast a muted red light over the landscape.

The others emerged behind him.

Nobody spoke for several moments.

They were standing on a road.

Not a narrow dungeon corridor, but a broad paved road that could once have carried enormous numbers of people. Buildings surrounded them on both sides. Some had collapsed completely, leaving piles of broken stone and twisted metal, while others remained standing despite missing entire sections of their walls. Several bridges connected the upper levels of different structures, and strange towers rose above the ruined skyline.

Jae-hyun slowly turned in place.

“This was a city.”

Subin nodded.

The evidence was everywhere. Broken transportation systems were embedded in the roads, massive plazas were scattered between the buildings, and faded symbols covered the walls. Whatever civilization had built this place had possessed enough organization and technology to construct an enormous urban center.

Ara checked her equipment.

“External signal is still unavailable.”

“Can you determine our position?” Director Kang asked through the internal communication system.

Ara shook her head.

“There is no connection to Earth. I can record our movement internally, but I can't transmit anything outside this environment.”

Subin looked at the sky.

There was no familiar sun.

The clouds moved strangely, and the red light had a different quality from natural sunlight.

“We're definitely not on Earth.”

Rafael looked at the surrounding ruins.

“If this is inside a dungeon, where are the monsters?”

A metallic scraping sound came from several streets away.

Everyone immediately became alert.

The sound came again, followed by several heavy footsteps.

Subin raised one hand.

“Wait.”

A group of humanoid figures appeared at the end of the road.

They were tall and heavily armored, with bodies made from a dark material resembling a mixture of stone and metal. Each carried a long weapon similar to a spear. Their movements were precise and synchronized, without the hesitation of ordinary monsters.

The system identified them.

[Ruined Sentinel — Level 171 — A+]

Six Sentinels stood in formation.

They did not charge immediately.

The lead Sentinel raised its weapon.

The others moved with it.

Jae-hyun's expression sharpened. “They're organized.”

Subin studied their formation. “They're guarding something.”

The Sentinels advanced.

Subin drew Simple Edge.

The first Sentinel attacked with a straight thrust aimed at his chest. Subin shifted aside and cut across the creature's weapon arm. His blade passed through the armored joint almost effortlessly, and the damaged section released a burst of red energy instead of blood.

The Sentinel immediately swung its remaining weapon.

Subin stepped inside its reach and cut through its chest.

The construct collapsed.

The remaining five attacked at once.

Jae-hyun and Liu Wei intercepted two while Ethan moved toward another. Yerin's spear struck a Sentinel's knee joint, disrupting its movement before she finished the construct with a second thrust. Rafael used his defensive ability to block an incoming strike while Diego attacked from the side.

Subin faced two more.

Their movements were coordinated.

One attacked from above while the other moved around his flank. Instead of retreating, Subin stepped directly between them, forcing their formation apart. The two constructs hesitated for a fraction of a second.

That was enough.

His sword passed through the first one's chest, destroying its core. The second Sentinel raised its weapon but stopped before completing the attack.

It looked past Subin.

Then it slowly lowered its weapon and began retreating toward the city.

Jae-hyun glanced at Subin.

“Why did it retreat?”

Subin watched the Sentinel disappear between the ruined buildings.

“It wasn't trying to fight to the death.”

Ara approached one of the destroyed constructs and scanned the remains.

“These aren't biological creatures.”

“What are they?” Yerin asked.

“Constructs. Their bodies are artificial, but they contain something similar to a mana core.”

Subin looked at the surrounding city.

“Then someone built them.”

Ara nodded.

“And if they were built, they probably had a purpose.”

The team continued deeper into the ruins.

The farther they traveled, the more evidence they found that the city had once been inhabited. Broken statues stood in large plazas, although the faces had been damaged beyond recognition. Strange symbols were carved into walls, while some buildings contained empty chambers filled with decayed machinery.

Several streets had large circular structures embedded in their centers.

Ara approached one and scanned it.

“This responds to mana.”

“Transportation?” Ethan asked.

“Possibly. There are several of them throughout the city, and their positions suggest that they were connected.”

Rafael looked at the ruined towers. “Whoever built this place had a functioning civilization.”

Subin remained silent.

He wasn't interested in guessing who had built the city without evidence.

The ruins could have belonged to humans.

They could have belonged to another species.

Or the dungeon itself might have created a representation of a civilization that never existed outside this environment.

Until they found something concrete, everything else was speculation.

The team eventually reached the center of the city.

A massive tower stood there, rising far above the surrounding ruins. Unlike almost every other structure, it remained almost completely intact. Its outer walls were black, smooth, and covered with faint red lines that pulsed like veins.

Four Sentinels stood before the entrance.

Their presence was immediately different from the others.

The system identified them.

[Ruined Sentinel Commander — Level 184 — A+]

Jae-hyun tightened his grip on his sword.

“These are stronger.”

Subin looked carefully at their positions.

“No.”

Jae-hyun frowned.

“They aren't guarding the entrance.”

Subin pointed toward the tower.

“They're guarding the entire structure.”

A pulse of red energy traveled through the tower.

The four Sentinels turned their heads simultaneously.

Then the entire city responded.

A deep vibration passed through the ground.

Dust fell from buildings.

One after another, ancient lights began activating throughout the ruins.

The transportation platforms glowed.

Broken bridges repaired themselves with streams of red energy.

Several towers extended upward as buried mechanisms activated beneath them.

Then thousands of red points appeared throughout the city.

Jae-hyun's expression changed.

“Those aren't lights.”

They were eyes.

Sentinels began emerging from buildings, underground passages, ruined stations, and collapsed structures.

Dozens became hundreds.

The expedition immediately formed a defensive formation.

Subin remained at the front, Simple Edge resting naturally in his hand.

Yet the Sentinels did not attack.

Every construct turned toward the central tower.

A massive door opened at its base.

A figure emerged.

It was significantly larger than the others.

Black armor covered its entire body, and a long sword rested against its shoulder. Unlike the other constructs, its movements were fluid, almost indistinguishable from those of a living swordsman.

The system identified it.

[Ruined Sword Commander — Level 203 — A+]

The Commander stepped onto the plaza.

Its sword lowered until the tip pointed directly toward Subin.

The meaning was obvious.

It wanted a duel.

Jae-hyun looked at Subin and smiled.

“This one's yours.”

Subin nodded.

He stepped forward.

The Commander moved without warning.

Its sword descended with tremendous force.

Subin shifted aside as the blade struck the stone, splitting the ground beneath him. He immediately answered with a horizontal cut.

The Commander blocked.

The collision produced a shockwave that scattered dust across the plaza.

Subin's eyes narrowed.

The construct's swordsmanship was refined.

There was no unnecessary movement.

The Commander followed with a sequence of attacks that flowed continuously into one another. Every strike prepared the next. A blocked attack became the foundation for another angle, while every retreat created space for a new attack.

Subin recognized the principle.

Continuity.

It was similar to what he had learned before, but the Commander's application was different.

It didn't merely maintain a sequence.

It used the opponent's response to construct the next sequence.

Subin allowed the battle to continue.

He blocked one strike, redirected another, stepped around a third, and countered the fourth.

The Commander adapted.

Its next attack changed direction halfway through the motion.

Subin barely avoided it.

A faint smile appeared on his face.

“This is interesting.”

The Commander accelerated.

Its sword became a blur.

Subin's movements became smaller.

Instead of meeting each strike directly, he began redirecting the force, changing angles and allowing the Commander's own momentum to create openings.

The battle moved across the plaza.

Around them, the rest of the team fought the Sentinels.

Yerin held a group away from the center while using her spear to control distance. Jae-hyun moved through several constructs with precise sword strikes, while Liu Wei attacked weak points whenever an opening appeared. Ethan's mana sword changed shape during combat, allowing him to switch between short and long weapons depending on the enemy's position.

Rafael and Diego protected Ara while she continued recording the battlefield.

The Sentinels were strong, but their movements were predictable.

The Sword Commander was different.

It learned.

Subin noticed it after the tenth exchange.

The Commander had begun changing its timing based on Subin's previous reactions.

Its sword no longer followed a fixed pattern.

Subin's eyes sharpened.

The Commander had adaptive swordsmanship.

The next attack stopped halfway through.

Subin had expected the blade to continue toward his shoulder.

Instead, the Commander twisted its wrist and changed the angle completely.

Subin redirected his sword just in time.

The blades collided.

Both combatants stepped backward.

The Commander immediately attacked again.

Subin entered its rhythm.

One strike.

Two.

Three.

Four.

The Commander's sword accelerated.

Subin's movements became increasingly precise.

Neither was attempting to overpower the other.

They were studying each other's decisions.

The Commander suddenly abandoned its continuous sequence.

Its sword stopped.

Subin reacted instinctively.

The construct used the interruption to create an entirely new attack.

Subin turned his wrist.

Simple Edge met the incoming blade.

The impact cracked the stone beneath them.

For a moment, the two swords remained locked.

Subin looked directly into the Commander's glowing eyes.

“You changed your pattern.”

The Commander pushed harder.

Subin's sword moved.

Rather than forcing the blade away, he allowed the pressure to slide along Simple Edge. His wrist turned, his body shifted, and the Commander's sword passed beside him.

Subin's blade reached the construct's chest.

He stopped.

The Commander remained completely still.

Subin lowered his sword.

The construct slowly lowered its own.

The surrounding Sentinels stopped fighting.

The entire city became silent.

A notification appeared.

[Combat Principle Recognized.]

[Adaptive Swordsmanship observed.]

[Personal Sword Path has incorporated new understanding.]

Subin looked at the notification for only a moment.

It wasn't a new skill.

There was no sudden increase in strength.

The system had simply recognized a principle that Subin had understood through combat.

That was enough.

The Sword Commander turned toward the tower.

The entrance remained open.

Subin understood the message.

He turned toward the others.

“Inside.”

The team regrouped.

Nobody followed them from outside.

The Sentinels remained in the plaza, motionless once again.

Inside the tower, the architecture changed.

The lower floors contained large rooms filled with broken machinery, but the deeper they went, the fewer physical objects remained. Instead, the walls became covered with enormous murals.

The first mural showed the city when it was alive.

The streets were crowded with strange humanoid figures. Large vehicles moved along elevated roads, while floating structures traveled between the towers. The civilization had been highly developed.

The second mural showed the city surrounded by enormous creatures.

The third showed the city under attack.

The final images showed the inhabitants leaving through circular platforms.

Ara stopped.

“Look.”

She pointed toward the final mural.

The circular platform was identical to the one through which the expedition had entered.

Except there weren't six.

There were dozens.

Each platform was connected to a different environment.

A forest.

A frozen landscape.

A volcanic region.

A city.

Floating islands.

An enormous ocean.

A desert.

And several environments they could not identify.

Rafael stared at the mural.

“These weren't entrances created recently.”

Subin nodded.

“They were already here.”

Ara moved closer.

The mural continued.

A group of figures stood before a massive circular gate.

Behind them, the city appeared empty.

The gate opened.

Beyond it was Earth.

The image was unmistakable.

There were mountains, oceans, and a familiar blue sky.

Everyone stared at it.

Jae-hyun finally spoke.

“Were they here?”

“We don't know,” Subin replied.

“But the mural shows Earth.”

“Yes.”

“Then someone from this place traveled there.”

Subin examined the image carefully.

There was no evidence of who the figures were or why they had opened the gate.

The mural simply showed the connection.

Ara suddenly noticed another detail.

“There are fewer figures in the final image.”

Subin looked.

The first mural showed thousands.

The later ones showed hundreds.

The final image showed only a small group.

Whatever had happened to this civilization, it had not ended peacefully.

But there was another important detail.

The gate in the final image was open toward Earth.

Subin turned away from the mural.

“We shouldn't assume the invasion came from here.”

Yerin nodded.

“We don't know whether they came through that gate or whether the gate was created for another reason.”

“Exactly.”

The expedition continued upward.

At the top of the tower, they found a circular chamber.

Unlike the lower floors, this room was completely intact.

A large crystal floated in the center.

Its surface displayed moving images.

The first showed the forest.

The second showed the ruined city.

The third showed a frozen landscape.

The fourth showed a volcanic region.

The fifth showed floating islands.

Several other images followed.

Ara stared at the crystal.

“It is monitoring the regions.”

Subin stepped closer.

The crystal changed.

A map appeared.

It showed a massive interconnected structure.

Each region was represented as a separate section, but all were connected through circular gates.

At the center was a large blank space.

Ara examined the display.

“There is something missing.”

“What?” Yerin asked.

“The central region.”

The map had several connected regions surrounding an empty center.

Then the crystal displayed a final line of information.

[World Dungeon Structure]

[Connected Regions: 12]

[Active Regions: 5]

[Inactive Regions: 7]

[External Gate Network: 6]

[Core Region: Sealed]

Subin's expression became serious.

The forest and ruined city were only two regions.

There were twelve.

Five were currently active.

Seven were inactive.

And somewhere at the center was a sealed region.

The crystal suddenly displayed another message.

[External Gate Network Synchronization: 18%]

Ara's eyes widened.

“What does that mean?”

Subin stared at the number.

“I don't know.”

The answer frustrated everyone, but Subin had no intention of pretending otherwise.

They needed more information.

The crystal shifted again.

A map of Earth appeared.

Six points began glowing across the planet.

The same six entrances they had discovered.

Then one of the points changed.

The platform beneath the staging facility disappeared from the map.

A new point appeared thousands of kilometers away.

Ara immediately understood.

“The entrance moved.”

Subin nodded.

The dungeon was not simply connected to six fixed entrances.

The entrances themselves were changing.

The crystal displayed one final message.

[Next External Gate Formation: 09:42:17]

A countdown began.

Rafael looked at Subin.

“What happens when it reaches zero?”

Subin looked at the world map.

“We're about to find out.”

The expedition had entered the ruined city expecting to discover the nature of the dungeon.

Instead, they had found evidence of an ancient civilization, a network of twelve regions, a sealed central core, and gates capable of appearing in different places across Earth.

The ruined city had given them answers.

But each answer had revealed a larger structure behind it.

Subin turned toward the chamber entrance.

“We've seen enough for now.”

Yerin nodded. “Return to the forest?”

“Not yet.”

Subin looked at the countdown.

“We wait for the gate.”

Outside, the ruined city remained silent.

Far beyond its walls, the crimson sky darkened.

And somewhere beneath the ancient streets, another section of the city began to awaken.