Chapter 6: The Algebra of War
The victory at the mall came with a price tag, and the currency was pain.
Obito woke up before the alarm, his body rigid. The adrenaline that had fueled his strike against the horned teenager had long since evaporated, leaving behind a deep, throbbing ache in his right shoulder. The prosthetic arm, which usually felt like a heavy, numb weight, now felt like a vice clamping down on bruised flesh. The impact had jarred the connection points, chafing the sensitive skin of his stump.
He lay in the dim light of dawn, staring at the ceiling. He tried to unstrap the harness with his left hand, his fingers clumsy with sleep.
Click.
The plastic limb came loose. He set it on the nightstand with a heavy thud. He looked at his shoulder. The skin was red and angry, inflamed where the socket had dug in.
"Stupid," Obito whispered to himself, his voice raspy. "Using a tool you haven't mastered to strike an enemy with superior mass. Reckless."
Kakashi would have scolded him. Minato-sensei would have given him a lecture on the difference between bravery and stupidity. But here, in this silent room with the snoring Kenji, there was no one to lecture him but his own ghosts.
He sat up, rubbing his face. Today was Monday. And according to the schedule pinned to the door, Monday meant "Integrated Studies."
School.
In Konoha, the Academy was about survival. You learned to throw a shuriken, you learned the history of the Great Nations so you knew who to kill, and you learned the theory of chakra. It was practical. It was life or death.
Here, school was... different.
The classroom at the Sunrise Home was a small, stuffy room that smelled of chalk dust and floor wax. Fifteen desks were crammed together, occupied by children who would rather be anywhere else.
Obito sat in the back row, his usual strategic position. He had his new notebook open. He had a pencil. He was ready to conquer this enemy just as he would conquer a rogue ninja.
The enemy, however, was a math problem written on the blackboard.
If a Villain creates a shockwave with a radius of 50 meters expanding at 20 m/s, and a Hero can run at 15 m/s starting from the center, calculate the time (t) before the Hero is overtaken.
Obito stared at the numbers. They danced on the green board, mocking him.
"Alright, who can solve this?" The teacher, a woman named Ms. Aida who had a Quirk that allowed her eyes to zoom in like camera lenses, scanned the room.
Obito looked down. Radius. Velocity. Time.
In his head, he tried to translate it to shinobi terms. Paper bomb blast radius. Shunshin speed. But the numbers didn't make sense. Why was the Hero running? Why didn't he just use a substitution jutsu? Or dig underground?
"Kenji?" Ms. Aida called out.
Kenji, who was balancing a pencil on his spider-like nose, jumped. "Uh... three seconds?"
"Wrong. You didn't account for the acceleration curve I wrote on the side. Anyone else?"
Her gaze landed on Obito. The new kid. The mysterious boy with the eyepatch and the missing arm.
"Obito-kun," she said, her voice kindly but firm. "You've been staring at the board very intensely. Do you have the answer?"
Obito felt the blood rush to his face. Every head turned to look at him. Even Jiro, who was spinning a pen in the front row, glanced back.
He stood up. That was what you did in the Academy when called upon.
"I..." Obito started. He looked at the diagram. "The Hero should not run. He should engage the Villain before the shockwave starts."
A few kids giggled.
Ms. Aida sighed. "While tactically sound, Obito, this is a physics problem, not a strategy meeting. We need the number. Can you solve the equation?"
Obito looked at the X and Y variables. They looked like foreign runes. He had never been good at book learning—he was the dead last for a reason—but this was a different language entirely. The education system of this world was centuries ahead of the Elemental Nations.
"I don't know," Obito admitted, his voice barely a whisper. He felt small. Smaller than when he was crushed by the rock.
"That's okay," Ms. Aida said, turning back to the board. "Sit down. We'll review the formula."
Obito sank back into his chair. He gripped his pencil so hard that the wood snapped with a sharp crack.
He wasn't just a cripple here. He was stupid. He was a dunce.
I am an Uchiha, he thought furiously, staring at the broken pencil. We are the elite. We are geniuses. Why can't I understand this?
The rest of the morning passed in a blur of humiliation. History class was a lecture on the "Quirk Laws of 2150," which sounded like gibberish. Literature involved reading a story about a boy who could talk to toaster ovens.
By the time the lunch bell rang, Obito felt mentally exhausted, his brain feeling as bruised as his shoulder.
He didn't go to the cafeteria. He couldn't handle the noise, the staring, the clattering of trays. He needed silence.
He wandered the halls until he found a door marked "Library."
He pushed it open. The room was cool and smelled of old paper—a scent that reminded him vaguely of the archives in the Hokage Tower. It was empty, save for rows of dusty bookshelves.
Obito walked to a secluded corner table and sat down. He pulled out his math textbook. He opened it to page one.
Algebraic Fundamentals.
He glared at the page with his single eye.
"You look like you're trying to set the book on fire with your mind."
Obito didn't jump this time. He recognized the footsteps. Light, rhythmic, scuffing slightly on the left side.
Jiro pulled out the chair opposite him and sat down. She had a sandwich in one hand and a carton of apple juice in the other.
"It's safe," Obito muttered, not looking up. "I can't use Fire Style here. The sprinklers would activate."
"Fire Style, huh?" Jiro took a bite of her sandwich. "You really commit to the bit. So, what did the math book do to offend you?"
"It exists," Obito said. He pushed the book away. "It's useless. When will I ever need to calculate the velocity of a shockwave? I just need to be fast enough to dodge it."
"True," Jiro agreed. "But if you want to go to a Hero High School, like UA or Shiketsu, you need to pass the written exam. And the written exam has math."
Obito froze. "Written exam?"
"Duh. Hero schools are elite academies. They don't just take muscle-heads. You have to be smart." She tapped her temple. "You said you want to be a leader, right? A... Hokage?"
"Yes."
"Well, leaders need to know how to count their troops. And calculate logistics. And understand physics so they don't drop a building on the people they're saving."
Obito slumped in his chair. She was right. Minato-sensei was a genius. He created his own jutsu. He calculated teleportation coordinates in milliseconds. Kakashi was a genius. He graduated at five.
And Obito? Obito was the boy who failed.
"I can't do it," Obito confessed, the words tasting like ash. "I don't understand the symbols. Where I come from... we didn't use this method."
Jiro looked at him. She saw the genuine distress in his eye. The bravado was gone, replaced by the fear of being left behind.
She sighed, putting her sandwich down. She wiped her hands on her jeans.
"Okay," she said. "Move over."
Obito blinked. "What?"
"Move your chair closer. I'm not shouting across the table."
Obito hesitated, then scooted his chair a few inches to the left. Jiro grabbed the textbook and spun it around.
"You're trying to memorize it," she said. "Don't memorize. Feel it."
"Feel... math?"
"Everything has a rhythm," Jiro said. It was her mantra. "Look at this equation. It's a scale. The equal sign is the balance point. Whatever happens on the left, has to happen on the right to keep the beat steady. If you add a snare drum here," she pointed to the X, "you have to add a snare drum there. Otherwise, the song falls apart."
Obito looked at the numbers. Balance. That... sounded like taijutsu. Or chakra control. Yin and Yang. Physical energy and Spiritual energy. If you added too much physical energy, the jutsu failed. You had to balance it.
"So," Obito said slowly, pointing at the +5. "This is... extra weight? Like a training weight?"
"Exactly," Jiro grinned. "To get the X alone—to free the ninja—you have to remove the weights. But if you take five pounds off this side, you have to take five pounds off that side."
Obito stared at the page. The chaotic jumble of numbers suddenly shifted. It wasn't random anymore. It was a formation.
*Target X is surrounded by guards (+5) and a multiplier (2). To assassinate X, I must first remove the guards, then divide the multiplier.
"Minus five..." Obito muttered, writing it down with his left hand. "Then divide by two."
"And the answer is?" Jiro asked.
"X equals... three."
Jiro clapped her hands. "Boom. Villain defeated."
Obito looked at the number. He felt a strange warmth in his chest. It wasn't the rush of combat, but a quiet, steady satisfaction. He had solved it. He wasn't stupid. He just needed a translator.
"You're... a good teacher," Obito said, glancing at her.
Jiro shrugged, looking a bit embarrassed. She played with her earphone jacks. "I'm not. I just hate seeing people struggle with the basics. My dad taught me music theory before I could walk. Math is just music without the sound."
They sat in silence for a while, the only sound the scratching of Obito's pencil as he attacked the next problem.
"Hey, Obito," Jiro said softly.
"Hm?"
"About yesterday. At the mall."
Obito stopped writing. "Did the police come?"
"No. But... why did you step in? You didn't know that kid. And those guys were way bigger than you."
Obito looked at his prosthetic hand, resting on the table. "Those who break the rules are scum," he quoted, the words echoing from a memory of a silver-haired rival. "But those who abandon their comrades—or the weak—are worse than scum."
He looked up at her. "I couldn't save... the people I wanted to save before. So I have to save whoever is in front of me now. Even if it's just a kid with an ice cream."
Jiro stared at him. Her eyes, usually bored and half-lidded, were wide. She saw something in him then. Not a broken orphan, but a spark of something intense, something ancient.
"You're weird, Uchiha," she said, a small, genuine smile breaking through her cool facade. "But... a good kind of weird."
"I'll take that as a compliment," Obito said.
"It is. Now do the next problem. If a train leaves Tokyo at 300 km/h..."
That evening, the pain in his shoulder had subsided to a dull throb. Obito stood in the backyard of the orphanage. It was dark, the moon hidden behind the city smog.
He wasn't throwing stones today.
He stood before the oak tree. He placed his left hand on the rough bark.
"Balance," he whispered. "Rhythm."
He closed his eye. He didn't force the chakra. He didn't try to explode it out of his pores. He listened to the flow of energy inside him. It was weak, trickling through scarred pathways, but it was there.
Left side equals right side. Balance the equation.
He sent a pulse of chakra to his feet. He adjusted the flow, matching the output to the resistance of the tree.
He stepped up.
One step.
Two steps.
Three steps.
He was horizontal, sticking to the side of the tree. He hung there for five seconds, defying gravity, defying his injuries.
Then, his concentration wavered. The equation broke. He fell, landing on his feet this time, though he stumbled slightly.
Obito didn't curse. He didn't punch the ground.
He looked at his hand. He looked at the tree.
"Three steps," he said.
It wasn't much. To the old Obito, it would have been nothing. But to this Obito, it was proof.
He was learning. He was adapting. He was solving the equation of this new life.
He turned and walked back toward the lights of the orphanage. He had homework to finish, and for the first time, the thought didn't terrify him.
As he walked, he didn't notice the faint, momentary prickle in his right eye socket—a ghost of a sensation in the eye that was no longer there. A memory of power, waiting for the right moment to awaken.
Obito Uchiha was climbing back up. One step, one number, one beat at a time.