ch1-ch20 · 004-ch4

Chapter 4

It was a tale from after dinner one day.

That day, he was relaxing in the living room with his parents and his sister's family.

His sister brought Sai tea and asked him.

"Here's your tea. So, big bro, you getting used to life over here?"

"Thanks. Somewhat. Still thrown off by how peaceful everything is."

"Was the other world really that dangerous?"

"Well yeah. Had to hunt monsters every day and all."

As he was talking with his sister like that, his nephew chimed in.

"Monsters—like this?"

He said, shoving his smartphone in Sai's face.

On the smartphone screen was a small-bodied creature, resembling a hungry hell-ghost—a grimy-looking little imp.

"That's a goblin, isn't it. Huh? Why do you have a photo like this…"

"Then how about this?"

The nephew quickly swiped to show the next image.

"Gah, isn't that a Beholder…"

The Beholder displayed there was what adventurers would call a rookie-killer.

He showed various other monsters too.

"These are all monsters that show up in Shinjuku Tower, you know."

"That tower, huh…"

The tower. Commonly called "Shinjuku Tower."

Around the year 2000. A modern-day mystery that appeared in Shinjuku Gyoen.

Apparently, a huge fog suddenly appeared, and then it emerged along with a massive, strange noise.

This is how things played out back then.

When the police and Self-Defense Forces investigated the tower and surrounding area, they discovered a huge number of monsters inside. Because of that, the government decided to seal off the tower.

They reinforced the tower's perimeter with barricades and reportedly discussed how to handle the affected district.

Thirty-six hours after sealing the tower, a huge swarm of monsters poured out, and the police and SDF dealt with it.

This led to investigations inside the tower resuming anew.

Initially, they conducted sweeping operations with firearms, but after a while, monsters that firearms couldn't harm appeared. It was confirmed that attacks other than guns—like swords—were effective against them.

After that, they conducted internal investigations without using guns, but with firearms—the symbol and greatest invention of modern times—rendered useless, the tower's conquest made sluggish progress.

Afterward, they somehow managed to completely secure the tower's first floor and tried to gradually advance from there. But even then, massive numbers of monsters swarmed the first floor again.

That situation repeated many times, but from it, the tower's rules became clear.

1. If no one is inside the tower for about thirty-six hours, monsters come pouring out.
2. Use of firearms is basically prohibited. Even missiles don't work against monsters that guns can't harm.
3. Someone needs to be fighting twenty-four hours a day. Whether morning or night, someone has to be in combat.

It seemed the tower had rules like these.

But the SDF and police also had their regular duties. They couldn't focus attention solely on the tower due to personnel and budget issues.

Given this situation, the government decided to recruit civilian volunteers.

They decided to widely recruit people willing to fight monsters and aim for conquest in this game-like, fantasy-world tower.

These civilian volunteers came to be called "Adventurers"—an easily understood, widely recognized term—and that tower became known as "Shinjuku Tower."

And the slogan used for that recruitment went like this:

——Adventurers, conquer Shinjuku Tower——

Records show that the earliest adventurers were mostly martial artists, martial arts practitioners, or former SDF personnel. With them at the center, the conquest of Shinjuku Tower began.

A little while after that. People who could use techniques beyond the ordinary appeared among the adventurers.

Techniques that released a strange aura along the trajectory of a sword. People who could manifest what became known as "Skills" appeared. And then people who could use phenomena called magic began to emerge.

At first, these were phenomena that only occurred inside the tower, but gradually, people who could use magic outside the tower as well began to appear.

What is commonly called "Awakening."

These were measured in various ways, but at present, how Skills and magic manifest remains unknown. Traces thought to be magical power could be measured, but it was still a largely uncharted territory.

By the 2010s, even minors who had Awakened could receive entry permits if they were eighteen or older, and the tower's conquest had become a major trend spanning a quarter century.

It could even be said to have been woven into everyday life.

"I see…"

After hearing all of this, Sai recalled the time he was transported to Japan.

He'd been surprised to be able to sense magical power, but presumably, the tower was generating or activating it. In Sai's estimation, before the tower appeared, atmospheric mana must have been scarce.

By the standards of the other world, if there was this much magical power in the air, even natural-born mages could emerge.

If there's little mana in the atmosphere, one's internal magical power isn't generated.

In other words, no natural-born mages could exist.

This was just his guess, but he figured he wasn't too far off.

As he was vaguely thinking such things, his sister called out to him.

"So you ARE interested in this kind of stuff, big bro?"

His sister looked surprised as she picked at some side dishes.

"It was my job, after all."

Hunting monsters, reducing threats.

That was the adventurer's primary job.

He'd told his family what he did in the other world.

"The main job's monster extermination. Monsters spawn in places with dense mana or stagnant areas, so it's about wiping them out. And places like towers or caves—all generally called dungeons—have ores and treasures you can only find there. So you hunt monsters, gather materials… that sort of thing. Spent most of my life doing that kind of work."

An adventure fantasy like a game, but in another world.

His parents grimaced hearing this.

They never could have dreamed their own son was in such a dangerous place.

His nephew, on the other hand, listened with sparkling eyes.

For Sai, it hadn't been some adventure tale from a game or manga—it was a daily grind full of hardship and struggle. But he couldn't say he didn't understand the appeal.

"Come to think of it, do treasure chests and stuff appear in Shinjuku Tower?"

"Um, what was it… Something amazing came out, right? That shiny-shiny thing."

His sister didn't seem to really know.

"What Mom's talking about is the Thunder God Sword, right?"

"That's right, the Thunder God Sword!"

His nephew, for his part, spoke happily and showed him something called the Thunder God Sword on his smartphone.

Looking at the image, it was a sword with an incredibly ornate design.

"When the user specifies a target, they can generate lightning there."

"Huh, is that so…"

Sai's eyes widened as he listened.

Because he could tell it was different from the "Thunder God Sword" he'd seen in the other world. The other world's Thunder God Sword was a treasured blade said to have been literally bestowed by the god of thunder. He'd seen it once before, and the designs were far too different.

Going by what his nephew said, the performance was probably worlds apart too.

If all it did was generate lightning, even a store-bought sword with enchantments carved into it should be able to do that.

After that, his nephew kept telling him about Shinjuku Tower.

From what he heard, it seemed various materials and items appeared there, just as he'd imagined.

Monster materials and various items were apparently bought up by the government and companies, funneled into research and development across different fields.

Maybe because they were talking about the tower, his nephew spoke enviously.

"Lucky… I wanna go to Shinjuku Tower too."

"No way, it's a dangerous place…"

Sai's mother said worriedly.

"Haha, I get the appeal. If I were a bit younger, I'd go myself, maybe as a tourist."

His father, perhaps understanding his nephew's feelings, laughed like that.

"Maybe I'll go check it out."

Sai was currently unemployed.

He'd adapted to modern Japan, but since he'd turned the gold coins he'd amassed in the other world into ingots and sold them, he had assets and no need to work.

But in this peaceful daily life, he felt deeply uneasy about his body growing sluggish.

Because of that, he felt he needed to find some suitable work he could do.

If he became an adventurer conquering Shinjuku Tower, he could put his past experience to use—it might even be his dream job.

"Oh, you could definitely get in, big bro. I thought you could become one right away if you went to the Adventurer's Guild."

"Don't you need to get a license first?"

His nephew pointed out, correcting his mother's laid-back response.

"A license… I see. So it's a license system."

Even in the other world's Adventurer's Guild, there were licenses.

He nodded to himself, figuring it was probably similar.

"I'm looking forward to your streams, uncle."

"Huh, streams?"

According to his nephew, apparently everyone active in the tower was required to stream via camera. This wasn't for entertainment purposes—it was to prevent lawlessness in a place like the "Tower," where the law didn't fully reach.

"There's a channel the government prepared for the tower's conquest."

Saying that, his sister turned on the TV in the living room and connected to the internet.

She opened a channel labeled with the government streaming site, "Tower Tube."

Before entering the top page, a disclaimer appeared warning that "grotesque imagery may be displayed," and she pressed a button labeled "I Understand."

From there, his sister selected an adventurer's channel displayed as a recommendation.

A male adventurer conquering the tower appeared on screen.

The page displayed information alongside the stream screen—his real name, the floor he was conquering, and so on.

"So this is how it works."

For Sai, the thought of strangers watching his adventures felt uncomfortable. It was that privacy violation thing, probably. But seeing it displayed like this, he could see how it would deter anyone from trying anything shady.

Made sense—it led to crime prevention.

"So does this mean everyone currently inside Shinjuku Tower is shown?"

"That's the rule, yeah."

Right now, thousands of adventurers were streaming, and apparently, streams stopped only when leaving Shinjuku Tower. The male adventurer currently on screen seemed to be conquering the second floor with a three-person party.

"I get that it's for crime prevention, but won't people end up seeing unpleasant stuff? Like monsters getting killed, or these adventurers getting hurt. That's not something you can show to a mom, is it."

"AI puts mosaic over the blood parts, so it's not that scary."

"Ee-aye?"

AI had existed even when Sai was a child, but back then it was more of a sci-fi movie thing.

As he looked surprised, his nephew—who knew about this stuff—explained.

She changed the channel and displayed a party mid-combat.

This one was fighting a horde of goblins on the eighth floor.

Sure enough, heavy mosaic was applied over the injured adventurer's arm and the barely-alive, wound-covering goblins. According to his nephew, a computer automatically analyzed and mosaicked blood, corpses, and anything similar.

Also, if adventurers were seriously injured, the AI would detect it. An emergency alert would sound, and a rescue team made up of Adventurer's Guild elites would reportedly respond.

He'd been shocked by smartphones too, but Japan after thirty years felt like living in the future.

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Thank you for reading.

Today marks a two-chapter update.

Thank you very much.