ch01-ch20 · 002-ch01

Chapter 1

Hayasaka Toru is a dungeon cleaner.

Twenty years old, male, single. This year makes it his third.

Ever since the world merged with "the other world," dungeons — so-called labyrinths — appeared all across the globe, containing the sorts of monsters, rare treasures, magical relics, and monster materials that had previously only been spoken of in fantasy fiction.

Those who conquered these dungeons were called explorers, and a first-rate explorer was a modern-day hero. Everything they brought back from the labyrinths was exceedingly valuable, and some discoveries were significant enough to completely transform people's daily lives.

Not a day went by without S-rank explorers being featured on TV or in the newspapers. There were even explorers who carried out activities almost like idols.

There was supposedly a prophecy that a great king of terror would descend in 1999, and indeed, at the turn of the century, the world was transformed. It fused with a different world, becoming one.

Now, a quarter century has passed since then.

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"Uh, right... This is Toru. Starting the stream."

Hayasaka Toru — Toru — powered on his body camera at the entrance of the Sugai Dungeon, pulled his mobile device from his pocket to confirm the stream had started, then entered the "labyrinth" with an utterly unmotivated stride.

Heading down the slope from an entrance just barely wide enough for a large truck to pass through, he soon reached the dungeon's corridors. The walls, floor, and ceiling glowed faintly, making lighting unnecessary, though it was dark enough that you couldn't see thirty meters ahead.

Ambling through this dimness with a listless pace, Toru sensed a monster appear from the right at a four-way intersection and swung his weapon in his right hand overhead.

An iron bludgeon.

Strictly speaking, it was a homemade blunt weapon — five thin steel rebars, each cut to a length of one meter thirty centimeters, bundled together and welded, with hemp cloth wrapped round and round to form a grip.

What came bouncing toward Toru with a whizzing sound was a monster called a "Furball," ranging in size from a tennis ball to a volleyball.

Its method of attack: ramming.

It packed about as much power as a high school athlete throwing a basketball with all their might. Surrounded by a few of them, even a novice explorer might start to panic.

But for Toru, this was routine.

Sidestepping the bouncing body slam by just half a pace, he swung his bludgeon and knocked the Furball down. The Furball that hit the ground, he stomped under his foot.

He repeated this three times.

"Furballs, three."

Muttering in a voice just loud enough for the body camera's mic to pick up — yet utterly devoid of any spirit — Toru searched through the remains of the downed Furballs.

Basically, dungeon monsters vanish without leaving a corpse unless they drop materials. What they leave behind instead are "magic cores."

These are clusters of magical power, and in the modern world, they're used as an energy source superior to electric power generation. ...That said, the magic cores from monsters that appear on the upper floors of the Sugai Dungeon are only about the size of a grain of rice.

Even so, every little bit adds up.

He scooped up three rice-grain-sized magic cores and tossed them into his waist pouch. Then Toru set off again at his lackadaisical pace, cutting down every monster that crossed his path.

What appeared on the upper floors of the Sugai Dungeon were monsters called Furballs, Big Rats, and Demi-goblins. All of them were trash mobs so weak that it would be hard to struggle against them unless you were a complete beginner. Even rookie explorers stopped bothering with them before long.

"Rats, four." "Furballs, six." "Demi-gobs, two." "Rats, two." "Rats, three."

Strolling through the labyrinth, he pummeled, stomped, and kicked down every monster he encountered, one after another.

To be blunt, it was mind-numbingly dull work — but it was a job, so what could you do.

After the world fused with the other world, dungeons appeared across the globe, the continent of Atlantis surfaced in the ocean northeast of Australia, sea levels rose, and some erupting volcanoes were spared from damage by the breath of ice dragons.

Dungeons — labyrinths — had a characteristic: if left unattended, they would go on a rampage.

Apparently, when the magical power that builds up inside a labyrinth exceeds a certain threshold, powerful monsters that wouldn't normally spawn in that labyrinth appear, and with those monsters at the center, the labyrinth's creatures burst out into the outside world. This is what's known as a "Dungeon Rampage."

It's said to be like a cat coughing up a furball — the dungeon spits out the magical power it's hoarded too much of.

The labyrinths around the world were discovered precisely because they went on "rampages." Deep mountain gorges, ocean floors, uninhabited islands... In the early 2000s, when "Dungeon Rampages" occurred in all sorts of locations, the world was said to be a living hell.

Discovered labyrinths were placed under government control, and countries recruited explorers on a massive scale.

And so, humanity after the World Fusion achieved rapid adaptation, feeding on the various resources and knowledge produced by the labyrinths. Still, problems remained.

Indeed — even at this very moment, an undiscovered labyrinth could be rampaging.

Since it was impossible to search every corner of the world, undiscovered labyrinths ultimately just had to wait until they "rampaged."

Given that, at the very least, already-discovered labyrinds should be prevented from "ramping."

That's why even dungeons like the Sugai Dungeon — a D-rank dungeon that had already been fully explored, one that explorers paid no attention to — still needed a cleaner.

"Demi-gobs, three." "Furballs, two." "Furballs, four." "Rats, three."

Continuing his emotionless trash-mob cleanup, he pressed deeper into the labyrinth.

It had already been over two hours since he entered the labyrinth, but he hardly felt tired. Being able to swing a bundle of steel rebars for nearly two hours without issue had reasons beyond mere habit.

There was a theory that defeating monsters allowed you to absorb magical power.

The so-called leveling up.

Toru himself was born after the world fused — part of the so-called Other World Generation — and even in middle school, he had classes where they defeated monsters in dungeons.

Among humans who had absorbed magical power, there were rare individuals who manifested unique properties.

This wasn't limited to the Other World Generation — even among those who were already adults in 1999, there were people with high compatibility with the other world. People whose physical abilities rose abnormally from defeating monsters, people who became able to use magic, people who gained abilities that defied logic...

Naturally, Toru hadn't acquired a single one of those.

He had simply spent three years endlessly cleaning up trash mobs.

Even so, his physical abilities had improved enough for him to notice, and he probably had enough stamina to run a full marathon without issue.

But that was it.

S-rank explorers went without saying, but even as a C-rank explorer, Toru would be underpowered. The explorers making names for themselves weren't even human — they could run on walls and jump from the first floor straight to the third.

"Rats, two." "Furballs, four." "Furballs, four." "Demi-gobs, two... huh, what?"

Tossing the magic cores left behind by the monsters into his waist pouch, Toru tilted his head at a sense of wrongness.

He thought he'd heard something — a sound.

Toru pulled his mobile device from his pocket and checked the stream duration.

"Uh... right, four hours thirty-two minutes. There's a strange sound... I think. Kind of a... keeen... a sound similar to ringing ears. It might actually just be tinnitus on my end. Still, an anomaly is an anomaly, so I'll report it. Might as well leave a comment too."

To his stream with zero viewers and zero comments, Toru typed a comment himself.

After that, he stood still in silence for a while, but the tinnitus-like sound didn't go away.

"...Is this... picking up on the mic...?"

The usually familiar Sugai Dungeon felt strangely unrecognizable.

Not that he'd ever gone below the fifth floor, though.

"Should head back."

If anything seemed off, retreat immediately.

Even for someone who wasn't an explorer, as long as you worked a labyrinth-related job, this was common sense drilled into you until your ears bled.

On his way back from the third floor to the entrance, he clobbered every monster he encountered.

After exiting the labyrinth, his next stop was the city hall's Sugai Dungeon branch office.

Hayasaka Toru is a dungeon cleaner.

Three years into a commissioned contract with the city office.