Frictionless
Chapter One:
Kai Sato lived his life by a kind of silent, personal set of rules. These rules ran his days but didn't do much to calm the unease he always felt. He didn't trust in fate or destiny, or any vague ideas about how the universe worked. He believed in numbers, routines, and the steady, low hum of Suginami—a city that, like his own restless mind, never really got quiet. Every morning, at exactly 6:42 AM, his phone would buzz on his old wooden nightstand. A sharp synth sound, then a robot voice: "Class schedule check. Breakfast. Cursed technique ideation, time permitting."
He wasn't a Jujutsu Sorcerer, of course. That was clear. He was just Kai Sato, seventeen. He lived in a small, two-bedroom apartment with thin walls, sharing it with his quiet grandmother. His main tools were an oldish laptop with a faded sticker of Sukuna's domain, a growing need for caffeine from cheap instant coffee, and a habit of getting lost in anime forums. Jujutsu Kaisen had grabbed him from the first episode. It wasn't just the animation or the fights—it was the power system. How it was structured. How it made sense, almost like math. It was predictable, he thought, if you knew enough of the details. He often wondered if he liked it so much because his own life felt so messy and unplanned.
"Support role, definitely," Kai would often mutter to himself. He'd be leaning into his laptop screen, his face lit by its pale glow, frowning in concentration. He'd look at a spreadsheet he made that ranked cursed techniques by how much energy they used, how much damage they might cause, and how useful they were in a fight. He'd spent way too many hours trying to come up with his own technique. He did this even though he knew perfectly well his world had no cursed spirits, no evil sorcerers, and none of the scary, amazing energy that flowed through his favorite anime. Or at least, he tried hard to believe that, because thinking otherwise was too much.
The idea he was working on now, for months, was friction manipulation. It wasn't flashy like Gojo Satoru's Hollow Purple or scary-beautiful like Sukuna's Malevolent Shrine. But he liked how clever and subtle it could be. It was tactical, careful. It was a power that fit his brain better than raw strength ever could. Reduce the coefficient of friction beneath an opponent's feet to send them sprawling. Amplify it to lock them in an invisible vise. Alter the viscous drag of air around a projectile, or the resistive force of a blade against flesh. So many neat ways to use it, all from one basic idea.
But that was just a story, something for his notebooks and late-night online chats. That was the whole point, right? A safe place to think, to explore a world way more interesting than his.
"Kai!" His grandmother's voice, surprisingly sharp for her age, cut through the thin paper screen between his room and the small, always messy kitchen. "You'll be late! Again! The rice is getting cold, and your grandfather's picture will start judging you."
A tiny smile almost showed on Kai's face at the familiar words. "Coming, Obaasan," he called back, sighing softly. He closed the spreadsheet, but the detailed drawings of friction forces stayed in his mind. He put his worn notebook—full of messy notes, character thoughts, and drawings of hand signs—into his equally worn school backpack. The train to his very ordinary high school was a fifteen-minute walk. And Kai, in his own strange way of being organized but chaotic, was, as usual, five minutes behind the schedule he'd set for himself but always missed. He often thought he was just a set of bad habits, a program with too many pointless loops.
The morning air was that typical Tokyo grey. Low, heavy clouds covered the sky. The sidewalks were still dark and damp from a light rain that had stopped hours ago. Kai found a weird, sad kind of comfort in weather like this. Not cold enough to really hurt, not warm enough to make his summer uniform feel sticky. Just… quiet. Like his own mind, which was often lost in a fog of too much thinking.
He moved through the familiar city streets like he was on autopilot. He tended to slouch a bit, and his eyes often looked far away. Cross the narrow side street just as the walk signal started its loud, sharp beep—a sound he'd learned to ignore like background noise. Stay far away from the old man near the bakery who coughed loudly and theatrically, never covering his mouth—a small, predictable part of his morning routine. Weave expertly through the crowds of people going to work, like a ghost in the system, and slide into the train car just a second before the doors hissed shut. Same streets, same station sounds, same half-familiar faces that all blurred together. He had the trip timed, maybe not perfectly, but close enough that he could still pretend he was good at being on time.
His fingers twitched. He wanted to pull out his notebook and think more about how domain expansions were built, or maybe work on his latest idea about the energy patterns of different curse types. But the train was packed tight with people, a crowd of heads bent over glowing phone screens. Everyone was lost in their own little digital world. So, he leaned his head against the cool window glass, his eyes half-closed. He let the muffled sounds of broken conversations, ads, and train announcements wash over him. He often felt strangely separate in crowds, like he was watching everything from behind a one-way mirror.
"…heard about it? Another one of those weird explosions… near Shibuya last night, they said…"
"…gas leak, that's what they're saying. Always a gas leak, right? Easy excuse."
"…felt it all the way in Setagaya. My cat went totally nuts…"
Kai's eyes narrowed just a tiny bit. He didn't believe the official stories anymore. Too many of these "coincidences" were happening, too often. They were like errors in a program that was usually stable. He'd been quietly keeping track of them for months—short news articles hidden deep in online papers, quiet rumors on conspiracy websites that disappeared fast, even blurry, shaky phone videos that showed up online for a bit before being taken down by someone. Shadows that stretched in weird, impossible ways. Blurry shapes that moved at the edge of the video, too fast to see clearly. More than once, he'd paused a video, his breath catching, his heart beating a little too fast. He'd seen something that looked way too much like the scary outline of a cursed spirit from the anime. But that was crazy. Impossible. Wasn't it? Just his eyes playing tricks, his brain seeing patterns because he'd stayed up too late.
But a stubborn, disloyal part of him wanted it to be true. Not that he wanted a real invasion of evil curses or super-powerful sorcerers in his ordinary world. But he wanted something. Something more. Something that could explain why he always felt… not quite connected. That strange feeling, especially when he was alone, that the world wasn't quite sticking to him, like he was on a different wavelength. A ghost with weight, noticeable but never really part of things, always watching, hardly ever joining in.
School was a dull routine, a predictable program of teachers talking without much energy and classmates whispering to each other. Kai, as usual, stayed separate, watching. He kept his head down, not because he was shy, but because he was deeply uninterested. He knew it probably made him look stuck-up. He wasn't an outcast; he could talk to people, even make them laugh with a dry, quick comment if he felt like it or if the social situation needed it. He had… people he knew. But they didn't understand. They didn't see the world like he did—as a huge, amazing, complicated web of connected patterns, hidden rules, and complex chains of cause and effect that most people didn't seem to notice. They lived on the surface; he was always trying to figure out what was happening underneath.
"Sato, you ever think about joining the physics club?" Tanaka, a classmate who meant well, had asked him once during lunch. Tanaka had seen Kai sketching something that looked a lot like a flowchart for a binding vow instead of eating his lunch.
Kai had just shrugged, his face hard to read. "Too predictable," he'd said. Tanaka had looked confused. Physics, with its set laws and known numbers, felt like a puzzle that was already solved, a closed system. Jujutsu, though, was always changing, always evolving. It was scary and beautiful in its messy complexity.
After the last class, he skipped the usual student rush to karaoke bars and bright convenience stores. Instead, he went to his favorite quiet spot: the riverbank a few blocks from school, which was a bit neglected. Here, the city's constant noise softened to a distant hum. The gentle sound of water lapping against stones and the wind rustling through the tall, wild grass took its place. It was the perfect place to think, where his mind could stretch out. He took out his notebook. Its cover was soft and worn at the edges. He flipped past pages full of complex drawings of hand signs, detailed notes on cursed energy flow, theories about what triggered domain expansions, and even a half-hearted try at analyzing Gojo Satoru's teaching style. His handwriting was a wild mix of Japanese characters and English letters, with equations and quick drawings scattered around—messy, but clearly passionate. Focused.
He stopped at a page with a sharply folded corner. One word stood out in the middle, written in bold, careful strokes with his favorite ink pen: FRICTION.
Reduce kinetic friction beneath a target's feet to near zero – uncontrolled slide. Increase static friction to immobilize. Manipulate air resistance to alter projectile trajectory or create localized zones of drag. Enhance or nullify the grip of a hand on a weapon, or the cohesion of fibers in clothing. The interaction between surfaces… He'd written these first notes months ago, right after watching the Gojo vs. Toji fight again. He'd been fascinated by the impossible physics of their battle. The idea had grown from a quick thought into a full, detailed concept for a cursed technique—one that controlled movement and interactions by subtly changing forces between surfaces, without big flashy lights or huge amounts of energy.
It'll never be in the show, he thought, feeling that familiar sad wishfulness, a feeling he quickly pushed down. Too subtle. Not exciting enough for a big action series.
But he liked it. It felt like him. Logical. Efficient. Quiet. A reflection of how he wished the world worked.
That night, the Suginami city lights cast a pale, ghostly glow on Kai's bedroom ceiling. He was up much later than usual. The laptop on his desk felt warm and tired. He was rewatching the Shibuya Incident arc—the brutal, heartbreaking end of Season Two. The part that had broken the fandom, started a thousand online debates, and left him feeling empty and weirdly restless for days. Gojo sealed. Nanami… gone. Yuji, broken and screaming, carrying unimaginable power and unbearable pain. Sukuna, free and terrifying.
And then it hit him, harder and more urgently than ever. That familiar ache in his chest. But this time, it wasn't just him watching; it was a deep, almost physical pull. A desperate wanting. He wanted to be in it. Not for the killing, not for the pain—he wasn't into that. But for the pure, raw clarity. The solid purpose. Every character in Jujutsu Kaisen, good or bad, fought for something with a belief that was almost total. They had something to lose. They had determination. They mattered. Kai Sato, scrolling through websites and carefully listing fictional powers, felt like he didn't matter much, even to himself. He often didn't even know what he wanted for breakfast, let alone what he wanted from life. He just knew he wanted… more. More than tests, what society expected, and the gnawing emptiness of a future that felt already decided, boring, and totally without wonder or real meaning. He wanted a world where the rules, no matter how tough, were at least real, and where understanding them could actually change things.
The laptop screen flickered, acting strange. Once. Twice.
Kai sat bolt upright. His analytical mind immediately noticed the problem. A shock, like adrenaline, cut through his tiredness. "Power surge? Loose connection?" His tired eyes, usually half-closed in thought, were wide now.
The bright, destructive colors of the Shibuya scene on the screen started to twist and distort. They swirled into a sick-making, glowing spiral that seemed to pull at the air in the room. He reached for the power button, his fingers fumbling—too slow. A silent, blinding pulse of pure white light exploded from the screen. It filled the small room, wiping out everything in a sudden, overwhelming blast of senses. His laptop screen didn't just turn off; it shattered inward. It imploded with a soft, crystal-like pop that was immediately swallowed by a sudden, heavy silence.
The world, for Kai Sato, disappeared into complete, deep blackness.
When his mind slowly started working again, the first thing he felt was the sharp chill of cool, damp stone under his hands and on his cheek. Mist, thick and ghostly, curled around the edges of what he could see. It smelled of old earth and something else… something sharp, electric, and totally new. The air itself felt completely different—heavy, not in a way that choked him, but like it was filled with a strange, real presence, as if it held the weight of long-lost history and strong, sleeping feelings.
He pushed himself up slowly. Every muscle complained. His head throbbed with a dull, steady ache. His heart hammered against his ribs like a trapped bird. For a scary moment, his analytical mind froze, overloaded by raw feelings and information it couldn't quickly sort or explain. He was lying on stone, cold and uneven. The stars burning in the black sky above were like nothing he'd ever seen from Tokyo—too many to count, piercingly clear, and forming strange, amazing patterns.
And then he saw it. The structure rose out of the swirling fog like something from a dream made terrifyingly real. Two massive stone gates, worn down by centuries. Faded, complex kanji were carved into them—kanji he knew instantly, impossibly. Old, fragile talismans clung to the dark wood, along with thick shimenawa ropes that seemed to almost glow with an aura of… something ancient and incredibly powerful.
There was no doubt. No spreadsheet, no online post, no slow-motion video analysis could have prepared him for this crushing, undeniable truth.
It was Jujutsu High.
And for the very first time in his seventeen years of carefully ordered, rule-driven life, Kai Sato felt the ground under his feet hum with a bright, unexplainable energy. He couldn't analyze it, couldn't measure it, but he could absolutely, terrifyingly, feel it. The world, it seemed, was finally, truly, sticking to him.