One Day in Tokyo, Japan, 2025.
One day, an 18-year-old young man named Yamiya Samede collapsed on the balcony of his house. Holding a book, he had been lying there for about three hours.
What exactly happened?
Three hours earlier...
"Hello, Azakari, it's your brother. Why haven't you called me back this late?"
A woman's laughter echoed through Yamiya's phone.
"Hello? Azakari, this isn't the time for jokes. Do you want me to pick you up or not?"
However, the voice that responded was not his younger sister Azakari's but someone else entirely.
"Yamiya... finally, my revenge is complete."
A girl's voice spoke through the phone.
"Wait, who are you? You're not Azakari!"
"Of course not, idiot. Have you already forgotten me? It's Shiyanade, your childhood friend."
Yamiya immediately responded.
"Shiyanade? You... what have you done to my sister? Where is she?"
"Tch, such a dumb older brother. No wonder your sister is just as stupid!"
Shiyanade turned on her phone camera, showing Azakari.
"Brother, help! This woman is holding me hostage!" Azakari cried out.
"You... you bastard! What have you done to my sister?!"
Yamiya hurried to his motorcycle, ready to go.
"Hold on. You should check your balcony first and see everything for yourself," Shiyanade said.
Yamiya rushed to his balcony. From there, he saw a convoy of excavators and trucks lining up toward his house.
"I've prepared a special surprise for you, Yamiya Samede..."
Shiyanade ended the call and sent a picture of Yamiya's father's unpaid debts and his mother fleeing abroad.
"No... this must be fake, right? There's no way..."
Just then, a bank agent arrived, dressed in a black suit, red tie, and sunglasses. He forcefully broke through the gate, followed by several men who started confiscating Yamiya's belongings.
"Wait! Give me a few months, I'll pay it back! Please, don't do this!" Yamiya pleaded.
But it was too late. Abandoned by his parents without any preparation, Yamiya had no money left in the bank, and his debts had reached their limit. Not long after, Yamiya lost consciousness on the balcony.
...It's not over yet...
An earthquake struck Tokyo, measuring 6.3 magnitude. The tremors caused cracks in the ground, which gradually grew larger, forming several sinkholes, including one right in front of Yamiya's house.
People fled in panic, running in all directions, desperate to escape. But Yamiya, even after waking up, remained still, unfazed as if nothing was happening.
The bank agents abandoned their work and ran away, leaving a massive excavator in front of his house. A transport truck fell into the giant hole.
Yamiya remained calm. Standing on the balcony with his hand on the railing, his expression was blank, his body fueled by adrenaline.
And then, a monster appeared to destroy Tokyo—a Kaiju, more specifically Kaiju-99, emerging directly from Yamiya's house.
Yamiya was flung into the air like dust.
As he fell, the Kaiju looked at him and, without hesitation, swallowed him whole.
---
Moments later...
*System: Congratulations, Mr. Yamiya, you have been granted a second chance.*
"W-what?"
Yamiya woke up, unaware that he was inside Kaiju-99's stomach.
"This... is this the inside of a Kaiju? It stinks!"
Overcome by the stench, Yamiya felt like throwing up.
He sat against the stomach wall, lost in thought—not shocked, not curious, just waiting to be turned into Kaiju waste.
But then, the system spoke.
*"Don't give up. Why is a man as weak as you?"*
Yamiya was shaken. He thought he was hallucinating, but it was simply the words of the system he had received.
"Who are you?"
*"I am your system. Without further delay, could you press me?"*
"Alright."
Yamiya pressed the system screen, revealing a new option.
*"Now press 'Yes'."*
Without reading the consequences, Yamiya simply agreed.
Suddenly, his body transformed into a machine—a production printer, resembling a factory conveyor system.
"What is this? Another ridiculous thing?"
Yamiya sighed.
*"Oh dear, Mr. Yamiya, try to be a little happier. Now press the button—"*
Before the system could finish, debris from a fallen helicopter dropped into the Kaiju's stomach, shattering upon impact. But that wasn't all—several animals from Tokyo Zoo tumbled in as well.
It seemed Kaiju-99 had been devouring zoo animals while being attacked by the military.
*"This is a great opportunity. Now, use your skill."*
Yamiya's machine started printing golden "S" letters, gleaming like solid gold bars.
*"1... 2... Alright, let's give these injured animals the letters."*
"Huh? For what?"
*"You'll see."*
The system sent the golden "S" letters toward the animals. Upon contact, the letters entered their bodies, healing their wounds and restoring them.
*"Congratulations, Yamiya has acquired six tigers."*
"Whoa, that actually worked?"
Yamiya was mildly impressed.
*"Yes, but now we're going to do something even crazier..."*
*"We're going to tame the creature we're inside of."*
"The creature we're inside of...? Wait… this Kaiju??"
*"Yes. The chances are low, but better than nothing, right?"*
Yamiya started mass-producing golden "S" letters, as many as possible.
*"6...7...8... production limit exceeded!"*
"Alright, this is our best shot..."
The system confirmed, launching all eight letters at once. They attached to the Kaiju's body.
A bright white light burst forth, and the system chanted an incantation. After two minutes, they succeeded in taming the Kaiju.
Coincidentally, outside, the Kaiju had been struggling against the well-coordinated military. But now, under Yamiya's control, the Kaiju regenerated its body.
The Kaiju rampaged, its tail sweeping through military vehicles. A barrage of energy missiles erupted from its stomach, striking helicopters.
The Kaiju defeated the military, but civilian reinforcements had already been called. Knowing this, Yamiya commanded the Kaiju to retreat into the ocean.
The Kaiju ran toward the shore, demolishing everything in its path—hotels, restaurants, even a car dealership.
Soon after, reinforcements arrived, but it was too late. The Kaiju had already disappeared into the sea, leaving no trace.
---
In the Ocean.
Now tamed, the Kaiju was given a new name. Previously known as "Kaiju-99," which referred to the 99th recorded Kaiju appearance in Tokyo, Yamiya renamed it "Salki" in the Kaiju-Japanese language.
The name meant "18 is now tamed."
Like all named monsters, Salki grew stronger and could now communicate with its master.
And thus, Yamiya, once lost and hopeless, had found a new purpose.
He would take revenge on Shiyanade.
And rescue his sister, Azakari.
The night began to fall, marking the start of the "Kaiju" month. This year, Kaiju births had drastically increased compared to previous years. In America, there were 400 Kaiju, while in Western Europe, only 20. However, the latest record was in Japan, where approximately 70,000 Kaiju had grown to full size.
But how could they still survive? How could humanity still survive? It was because Kaiju in that era were divided into three categories.
1. Normal Kaiju
These Kaiju emerged from within the Earth's depths. However, their true origin was not actually from the Earth's core. Instead, they appeared from a dimension that manifested through the layers of soil underground, meaning they came from another world.
2. Dormant
This type of Kaiju was the reason why Earth remained relatively safe despite the numerous Kaiju appearances. That was because they only appeared briefly—some only for ten seconds, others for a day before being abducted by aliens, and so on.
3. Unknown
Kaiju that had not yet been classified. To this day, the Hiesha Era and the Volcano de Kaiju Era were considered part of the Unknown category. In reality, these creatures were not truly part of the Kaiju family but were alternate versions of their ancestors.
And Kaiju Salki belonged to the first category.
---
That night, Yamiya arrived in northern Japan. He was well aware of Shiyanade's former residence, but he also knew that Shiyanade had moved out two years ago. Thus, he intended to seek clues from the current homeowner.
Upon entering a city, the residents immediately panicked. Lights in the residential areas were switched on all at once—an initial response to a Kaiju invasion. Yamiya took command immediately, launching a barrage of light missiles that terrorized the surroundings.
"Congratulations! Crime points have increased."
Crime Points +2
Crime Points +2
Crime Points +2
Crime Points +2
Crime Points +2
Crime Points +2
"So this is what it feels like to be a villain in a comic? Why does it feel so inhumane?" Yamiya muttered while continuing to destroy houses.
The system continuously converted his crime points into stats that strengthened the Kaiju. Meanwhile, they were getting closer to the location of Shiyanade's former home.
Upon arrival, the house was gone—only an empty plot of land remained. Seeing this, Yamiya was enraged and began wreaking further havoc on the area.
However, a teenage boy around Yamiya's age attempted to stop him. He had orange hair, a yakuza-like appearance, and seemed determined to confront the Kaiju in front of him.
Unfortunately, he didn't realize that Salki would devour him immediately. At first, it was just a chase, but in the end, the boy was swallowed whole.
Inside the Kaiju's stomach, the boy came face to face with Yamiya. The system asked why Yamiya had targeted him.
Yamiya responded,
"The Shiyanade family is famous for their ugly faces and orange hair at school."
Right in front of him stood Shiyanade's father.
"Wait, do you know where my son is!?"
"I should be the one asking first. Where is Shiyanade?"
Both of them were searching for Shiyanade, yet neither had any answers.
"Ugh… Damn it… Even as his father, I don't know what happened to my own son."
"Sir, could you tell me what happened before?"
Thus, Shiyanade's father told him everything.
Shiyanade had once been rejected by the boy he deeply loved. He had prepared a restaurant and an entertainment venue for a date, only to be rejected outright.
His heart shattered, but he never told his parents. Instead, he ran away from home, taking his father's credit card with him.
His parents searched for him for an entire year, but they never found him. Then, in October, his mother suffered a heart attack and could not be saved because the nearest hospital had been destroyed by a Kaiju.
Left with no choice, Shiyanade's father lived alone and became a yakuza—a scourge of society.
That was the story of Shiyanade's father.
However, he went on. He wanted Yamiya to find his son, and in return, he would offer all of his employees from his "rental girlfriend" service.
But if Yamiya failed, he would not help return his son, as that was all he had left to offer. He then proposed a negotiation.
Yamiya, whose mind was already twisted, asked:
"How many?"
"Ten."
"Ten? That's not enough."
"What!? But that's all my employees..."
That seemed to be the end of his bargaining power.
With limited time before the military arrived, Salki was preparing to eject Shiyanade's father through the lower digestive system.
But the man was desperate.
"Wait! What if I become your girlfriend!?"
"Uhh, my sister!? My older sister, then!"
"I beg you!! What about... my mother!? Oh, I know! You like older women, don't you? How abou—"
Shiyanade's father was promptly expelled into the sewers as Salki hurried back to the ocean.
"Tch, damn perverted yakuza," Yamiya scoffed.
"You say that, but you were interested too!" the system remarked.
"Ah, no, I was just toying with him to make him even more depressed. From the start, I had no intention of helping the Shiyanade family. Not even a little..."