Chapter Text
Chapter One: The Saiyan and the Hikikomori in an Unknown World
The comforting aroma of freshly cooked rice and the sound of his granddaughter's laughter filled the dining room. It was a peaceful night on Mount Paozu. Goku was sitting at the table, devouring a mountain of food while Chi-Chi smiled, happy to have her husband at home. Goten excitedly discussed his studies with Videl, while Pan, now a bit older and sporting a somewhat delinquent attitude—a result of spending so much time traveling across the universe alongside Trunks—tried to steal a piece of meat from her grandfather's plate.
Goku laughed, pulling the plate away from Pan with a swift movement. He had promised. After the exhausting and nearly fatal battle against Baby Vegeta, which threatened to decimate everything he loved, Goku swore to spend more time with his family. The last clash had been a nightmare. Baby Vegeta's power level with "Ultra Ego" had almost obliterated him from existence. If Goku hadn't fused the colossal and primal power of Super Saiyan 4 with the divine purity of God Ki, achieving the legendary Super Saiyan 4 Blue, Earth would no longer exist. That transformation changed him, matured his mind, and permanently stabilized his body in his adult form. He was no longer just a warrior looking for fights; he was a protector, a father, a grandfather.
"Grandpa, pass that meat already!" Pan exclaimed with a rebellious pout, though her eyes showed the immense affection they had for each other. Their space journey had made them inseparable.
"You've got to be faster than that, Pan!" Goku laughed, about to take a bite of the meat.
And then... the world blinked.
There was no Ki explosion, no visible dimensional rift, no distortion in space-time that his sharp instincts could foresee. Just a sudden flash, and the sound of his family's laughter was replaced by the cacophonous noise of wooden wheels, heavy footsteps, and unknown voices.
Goku blinked, confused. The meat had vanished from his hand. The dining table disappeared.
He was standing in the middle of a cobblestone street. The sun shone brightly in the sky. People hurried past him.
"Huh? Chi-Chi? Goten? Pan?!" Goku called out, spinning around. His voice was lost in the hustle and bustle of a medieval market.
The warrior wore his iconic blue gi with yellow pants, the same one he had worn on his travels across the universe at the beginning of his cosmic journey with Pan and Trunks. He looked at his own hands, then at the people around him. Lizard-men pushing carts, people with dog and cat ears, shining armors.
Goku's mind, sharpened by decades of combat and the mastery of divine Ki, began to process the situation almost immediately. This isn't Earth. But it's not any planet I know, either. Is it an illusion? Magic?
He closed his eyes and placed his index and middle fingers on his forehead, trying to focus his spiritual perception. He searched for familiar signatures. Vegeta's overwhelming Ki, Gohan's serene energy, Piccolo's firm presence. Nothing. There was an absolute void of any familiar presence.
Calm down, Goku. Think, he told himself. If I'm not on Earth, maybe I'm in Universe 6?
He tried to extend his senses even further, searching for divine presences. Lord Beerus? Whis? Supreme Kai? Hit? Cabba? He projected his thoughts through the basic telepathy the gods had taught him. No answer. The void he found wasn't just physical distance; it was a barrier that transcended the twelve universes.
Goku opened his eyes, his expression hardening, revealing the maturity of a warrior who carried the weight of countless battles. The energy of the people around him... their Ki was there, but it was profoundly bizarre. It was as if it was mixed with the air itself, an external energy flowing through them—something he deduced to be some kind of mana or magic inherent to that world, rather than the internal life force he knew as Ki.
Goku's heart tightened. Not out of fear of the unknown, but out of concern. Who will protect Earth? My family? Baby Vegeta was defeated, but threats never stop appearing. If I'm not there...
He clenched his fists. He needed to go back. Immediately.
His first idea was to raise his Ki, force the Super Saiyan 4 Blue transformation, and scream to tear through the dimension, exactly like Gotenks and Majin Buu did in the Time Chamber. But he hesitated. With the absolute and overwhelming power he possessed now— recklessly tearing space-time could cause a universal collapse. He could accidentally destroy this inhabited world, or end up falling into an eternal dimensional void where he'd never find his way back.
He reached into his pocket and felt the small metallic device. The Zeno Button. It was the perfect solution, right? Call the Omni-King.
Goku squeezed the device through the fabric, but swallowed hard. No. If I call little Zen-oh here, and he realizes this is a world or universe outside his jurisdiction, or simply finds the place "ugly" or "boring"... he might erase this entire dimension.
The memory of Future Trunks' universe being erased flashed in his mind. The absolute white void. The guilt of not being able to save that universe. Goku couldn't make the same mistake. He wouldn't risk the lives of billions of innocents just to shortcut his way back home.
"Damn it..." Goku muttered, letting go of the Zeno button. "There has to be another way. I need to figure out where I am first. Someone here must know what's going on."
He started walking, closely observing the architecture and the society. He needed information. However, amid the fox ears and dragon scales, his eyes caught something peculiar near a stall selling apples, or what looked like apples.
It was a boy. An ordinary young man with short black hair, wearing clothes completely different from everything around him, but familiar to Goku. A tracksuit. That boy exuded a different aura from the rest. It was the aura of someone displaced, someone from Earth.
The boy was mumbling to himself, looking frustrated after being shooed away by a sturdy-looking vendor. Goku decided to approach, completely hiding the presence of his Ki so as not to scare anyone.
Meanwhile, a few meters away, Natsuki Subaru was born during the Heisei era in a Japan with an educational system completely free of any pressure.
He had lived for seventeen years, and describing his life would take seventeen years. Leaving that aside, his current situation could simply be described as "third-year high school student, shut-in."
After realizing he had been summoned, the first thing Subaru tried to do was negotiate with a "Merchant?". When he tried to buy "Apples?" with his Japanese Yen, he was immediately rejected. It seemed this world used gold, silver, and copper coins. Subaru checked his belongings. A cell phone with no battery, a wallet with useless yen, snacks, and cup ramen.
Subaru walked into a dark alley to organize his thoughts, sitting on the cobblestone ground.
Subaru: "The situation is disastrous. And, of course, I don't know why, I don't even have memories of stepping through a mirror or jumping into a pond. More importantly, where is the beauty who summoned me? The lack of a heroine to greet me is absurd! What the hell am I supposed to do?"
He was complaining to the wind when a shadow blocked the sun above him.
"Excuse me." A deep, masculine, and extremely calm voice sounded.
Subaru jumped, startled, and looked up. Before him stood a very tall adult man with a physique that seemed carved out of granite. His black hair was impossibly spiky, and he wore a blue martial arts uniform with yellow pants and red wristbands.
Subaru: "W-Whoa! W-Who are you? Wait... that black hair... those exotic clothes but made of normal fabric... Are you Japanese?!"
Goku blinked, relieved to hear his language so clearly. He gave a slight smile, an attempt to look friendly, though his gaze remained sharp and analytical.
Goku: "I'm Goku. Son Goku. And yes, I'm from Earth, although I wasn't born there. I noticed you're from there too by your clothes and the lack of that strange energy the people of this world have."
Subaru blinked in disbelief. The guy was huge, smelled of confidence, and looked like he stepped out of a 90s shounen manga, but he spoke his language.
Subaru: "Earth? You mean Japan, right? My name is Natsuki Subaru! Man, what a relief! I thought I was the only unlucky guy who suddenly got swallowed into an isekai! So you were summoned too? Where's the princess who brought you? Did you get some overpowered cheat skill?"
Goku crossed his arms, analyzing the boy's torrent of words. Isekai? Summoned? Overpowered cheat skill?
Goku: "Isekai? What's that? Look, I wasn't summoned by anyone, I think. I was having dinner with Chi-Chi, Pan, Goten, and Gohan and Videl. You know, my family. Out of nowhere, I appeared in the middle of the street. I tried to teleport back, but I can't track anyone's Ki from Earth. I tried telepathic contact with Lord Beerus and Whis, I even wondered if I wasn't in Universe 6, but nothing. It's like my whole universe is blocked off. I need to find a way back home, Subaru. Do you know how?"
Subaru stared at the middle-aged man for five long seconds, silence filling the alley.
Teleportation? Ki? Lord Beerus? Universe 6? Subaru's mind tried to put the pieces together. Ah... I get it.
Subaru (thinking): This guy is a middle-aged Chuunibyou! He must be one of those fanatic cosplayers who got lost in character. And worse, his brain completely fried from the shock of ending up in this world. But... he said he was having dinner with his family. Wife, grandkids, kids...
Even though Subaru despised many things, seeing the genuinely worried and serious look in the strong man's eyes broke the boy's cynicism. Goku didn't seem to be joking. His expression was that of a father terrified for his family's safety.
Subaru scratched the back of his neck, sighing.
Subaru: "Look, 'Goku-san'... I hate to break it to you, but according to the rules of an Isekai, which is what we call this kind of parallel fantasy world, you can't just 'go back home'. Usually, you're summoned for a reason. You have to find the princess, get a holy sword, defeat the Demon King, and maybe, just maybe, the gods will send you back."
Goku's expression darkened in a way that made the air around them suddenly feel denser and heavier. Subaru felt an instinctive chill run down his spine, a feeling that if that man wanted to, the entire city would turn to dust.
Goku: "Demon King? Like Dabura or Piccolo Daimaoh? I don't have time for this, Subaru. The Earth I come from is always in danger." Goku's voice sounded incredibly grounded, carrying the wisdom of universal battles. "Several threats have appeared over the years to destroy it. The last one was Baby Vegeta... it was the hardest battle of my life. His Ultra Ego almost annihilated everything. If I hadn't broken my limits and reached Super Saiyan 4 Blue, mixing the power of the gods with Saiyan fury... I don't know what would have happened."
Subaru's eyes widened. Super Saiyan 4 Blue? Baby Vegeta? Ultra Ego? Man, this lunatic's schizophrenia is incredibly specific and detailed!
Goku closed his eyes, his frustration showing.
Goku: "If a strong enemy appears right now, Gohan, Piccolo, and Vegeta will have to handle it. But Vegeta is still recovering from Baby's possession, and Gohan works too much... I promised Chi-Chi I would be there. I need to protect my family. I am the strongest in my universe, I can't stay stuck in another dimension hunting demon kings while my home is unprotected."
Subaru, hearing that outburst, felt a lump in his throat. He was a useless shut-in who skipped school and disappointed his parents. But the man in front of him, although clearly "delusional" with stories of Ki, gods, and alien transformations, was motivated purely by love and duty to his family. Goku was everything Subaru felt he wasn't: a responsible adult.
Subaru felt pity. A lot of pity. Poor Goku was in a state of total denial and trapped in a dangerous world without knowing he was just an ordinary human (in Subaru's view, of course).
Subaru patted his own chest with an encouraging smile, forcing an optimistic tone.
Subaru: "Don't sweat it, Goku-san! I understand! You're a hero, you have a family waiting for you. Look, I'm new to this too, and my social skills are level 1, but... we're fellow Earthlings! I'll help you get back to your Chi-Chi and the rest of the gang. If we have to defeat this Demon King guy, we'll defeat him together! Or rather, with my gaming knowledge, I'll guide you!"
Goku looked at Subaru. His intense black eyes studied the fragile boy. He could feel it; Subaru was weaker than Mr. Satan. His power level must be around 5, at most. But there was honesty and a newly discovered spark of courage in his words.
Goku relaxed his posture and offered a genuine smile, the famous comforting smile of Son Goku.
Goku: "Really? Wow, thank you so much, Subaru! You seem like a nice guy. But if we have to fight, stay behind me, okay? I can't sense your Ki properly, but you seem pretty fragile to me. I don't want you to get hurt."
Subaru laughed nervously. He's completely nuts, but he's a nice guy.
Subaru: "Hehe, you got it, big guy. I'll handle the strategic part. But hey, seriously now... where do we st—"
Suddenly, Subaru's sentence was cut off. Goku abruptly turned his head toward the exit of the narrow alley they were in. His heightened senses picked up something moments before it happened. The smell of dirty sweat, cheap alcohol, and pure malice.
Heavy, irregular footsteps echoed. Three figures appeared, blocking the sunlight entering the alley's opening. Ragged men, with predatory smiles on their rough faces and rusty, yet lethal weapons in their hands.
Subaru took a step back, his instincts finally screaming in panic as the men's eyes locked onto him and the plastic shopping bag he was holding. The reality of the medieval Isekai clashed head-on with his fantasies, crushing them mercilessly.
???: "This is bad."