Naruto: Strongest Shinobi System With a Glitch

Before Kitazawa could finish processing the Body Substitution Jutsu, a commotion broke out.

"Kitazawa-sensei!"

Shibi Aburame rushed over, his voice low and urgent. "Someone's been infected by an explosive bug!"

Kitazawa's expression hardened instantly. "Take me there."

"This way." Shibi raised his hand, leading him forward.

Soon, Kitazawa found the afflicted Aburame clansman. The man unbuttoned his shirt, revealing a chest that bulged unnaturally, as if something alive pulsed beneath the skin.

Kitazawa's lips twitched despite the seriousness of the scene. 'Bro… you're growing an Alien.'

And disturbingly, the explosive bug did bear an uncanny resemblance to one.

"The insect has already absorbed quite a lot of chakra," Kitazawa observed, his tone steady, "but it hasn't matured yet. We still have time before it detonates."

He placed a reassuring hand on the man's shoulder. "Stay calm. I'll operate now."

"Thank you, Kitazawa-sensei!" the ninja said gratefully, adopting the same respectful title Shibi had used.

Kitazawa was well aware of the awkwardness of his position. Officially, he was just a Special Jōnin and an Academy instructor. Every Aburame present outranked him in status. Yet, because of his connection to Tsunade, they bowed their heads without complaint.

The surgery, however, was no simple task.

The explosive bug had fused almost completely with the host. Extracting it required not only elite medical ninjutsu, but also absolute finesse. Worse still, the creature was alive and aware. If it realized it was being removed, it would thrash in desperation, risking the host's life.

Minutes bled into hours.

Not far off, seven Aburame stood clustered together, watching in tense silence.

"His chakra control is terrifying," Shibi muttered, unable to hold back his awe.

They were in the field, so Kitazawa hadn't bothered to shield his work from view. Even without formal training in medical ninjutsu, Shibi could see how Kitazawa's chakra flowed like a surgeon's scalpel, carving the insect away without alerting it. The sight alone made his scalp prickle.

"He is Lady Tsunade's student, after all," one whispered.

Shibi coughed lightly. "Don't spread unconfirmed rumors. Lady Tsunade has her reasons for keeping quiet."

Not that it mattered much—every major clan had already accepted it as fact.

Finally, Kitazawa straightened, sweat dampening his brow. "It's done. The insect's out. Rest, and you'll recover."

The operation had lasted two grueling hours, leaving him drained but satisfied. Another high-difficulty procedure—successfully completed.

"Fortunate you were here," Shibi said gravely. "Otherwise, the consequences would've been unthinkable. On behalf of the Aburame Clan… thank you."

"No need for that." Kitazawa waved it off. "Did you secure the insect?"

Shibi produced a specially crafted bottle. "Yes. Here it is."

Inside, a cluster of larvae glowed faintly, dust-sized—like fireflies bottled up.

"Pretty," Kitazawa murmured, peering closer.

"The prettier, the deadlier," Shibi replied flatly.

"How will you handle it?" Kitazawa asked.

"We'll cultivate it, expand its numbers, and develop new secret techniques based on its traits," Shibi said with disdain. "The Nokizaru Group's use of it was crude and wasteful."

Kitazawa chuckled. "When it comes to insects, no one outmatches the Aburame."

"Are we returning to the village now?" Shibi asked. Somewhere along the way, his tone had shifted—addressing Kitazawa not as a subordinate, but as an equal. In the shinobi world, one did not make enemies of great medical-nin lightly. And Kitazawa, even without Tsunade, had already proven himself as one.

"Let's head back," Kitazawa said with a small nod. "If we're quick, I might even make it back to class."

"With your strength, why teach at the Academy?" Shibi asked, puzzled.

"Because I like it." Kitazawa smirked. He'd answered that question countless times. Ninja Academy teachers might have little prestige, but the work profited him. Strangely enough, Shibi's own son would one day follow the same path.

They set off. With one man injured, their pace slowed, and it was already Sunday evening by the time they reached Konoha.

"Kitazawa-sensei," Shibi said firmly, "no more words of thanks. If you ever need the Aburame Clan, we will answer."

"I'll remember that."

Kitazawa bid them farewell and went home. It was late, so he didn't bother Tsunade or Kurenai.

Glancing around, he noticed his general store still shuttered. He hadn't opened it for weeks, too busy at night to bother with business. Not that it mattered—between the Aburame and Inuzuka's combined gift of eight million ryō, he could afford to live comfortably for quite a while.

His thoughts drifted back to the Body Substitution Jutsu.

On paper, it was terrifying—able to replicate not just a target's appearance, but their ninjutsu, taijutsu, and even their thoughts. But it wasn't without limits. It couldn't replicate someone much stronger than the caster. Trying it on Tsunade, for example, would be like a pony trying to pull a freight train. Impossible.

Worse, it required the target to be in physical contact; no copying from afar. Compared to the Sharingan, that was a definite drawback.

Still, as a disguise technique, it was flawless. Unlike the standard Transformation Jutsu, which experts could pierce through, the Body Substitution was seamless. If every detail—appearance, chakra, even manner of thinking—was perfectly mirrored, even Kitazawa himself might not be able to tell the difference.

Monday morning, after breakfast, Kitazawa headed to the training grounds.

"Kitazawa-sensei."

Kabuto hurried over.

"Let me guess," Kitazawa said. "You've almost mastered Wind Release: Vacuum Blade?"

Kabuto shook his head. "Not quite. I actually wanted to ask—who's going to be our squad's final teammate?"

"With you and Torune, passing the Chūnin Exams won't be an issue," Kitazawa said, pausing. "As for the last member… don't worry. I already have someone in mind. You'll know when the time comes."

In truth, he had no one in mind. But that didn't matter—on registration day, he could always pull a genin at random.

Kabuto's eyes narrowed. Kitazawa's casual words confirmed his suspicions: Tsunade's dramatic raid on Root to rescue Torune had likely been driven by the need for teammates in the exams.

"Thank you, Kitazawa-sensei," Kabuto said, quickly shoving aside his swirling thoughts before heading back to practice.

Kitazawa, reminded of the timing, realized only a week remained until the Chūnin Exams.

His gaze slid to Sasuke. The practical combat drills had been ongoing for a week, with decent results—but Sasuke still needed to suffer a crushing defeat if he was to awaken his two-tomoe Sharingan.

A simple skirmish between two classes wouldn't cut it. No, the upcoming Student Council selection battles, with the whole school watching, would provide the perfect stage.

And if Sasuke's family—Fugaku, Itachi, and Mikoto—were in the audience, the pressure would be unbearable, just as Kitazawa intended.

Of course, for it to work, Sasuke needed hope. If he entered already resigned to defeat, the outcome wouldn't sting. Only when victory seemed possible—before being ripped away—would resentment ignite.

Kitazawa rubbed his chin thoughtfully.

"Sasuke."

The boy looked up.

"You've just about mastered the Leaf Exercise. Time to move on to something new."

Sasuke's eyes narrowed with curiosity. "What kind of exercise?"

The Leaf Exercise had been useful—he'd already noticed the improvement during his bout with Naruto last week. But against that absurd Multi-Shadow Clone technique, one leaf exercise wasn't nearly enough.

"I'll teach you the Shadow Clone Technique," Kitazawa said, a faint smile tugging at his lips.

In Class A, very few first-year students had ever managed to learn this jutsu. But Sasuke… he met the conditions. With his chakra reserves, producing two or three shadow clones wouldn't be a problem.

Sasuke's eyes lit up instantly. He knew the weight of what was being offered. After all, he'd been beaten black and blue by Naruto's endless swarm of clones more times than he cared to admit.

"Can I skip ahead and learn the Multiple Shadow Clone Jutsu instead?" Sasuke asked eagerly.

Kitazawa shook his head. "Your chakra isn't nearly enough to sustain that technique."

"Tch… I figured." Sasuke tried to hide his disappointment, but it lingered in his expression. Naruto's jutsu had always felt overwhelming, something Sasuke had secretly envied.

"The Shadow Clone Technique isn't about numbers," Kitazawa explained patiently. "It's about quality. With this jutsu, your strength won't just increase—you'll gain new strategies, new ways to outthink your opponent."

Sasuke's expression brightened. "That's true!" His mind immediately began racing.

He recalled Naruto's irritating knack for breaking free of genjutsu, but even that took a moment. If he and his clone alternated casting genjutsu in succession, they could stretch that brief delay. Even a single second would be enough to tip the battle in his favor.

Just as Kitazawa was about to speak again, glowing lines of text suddenly appeared before his eyes:

Current Mission: Help Uchiha Sasuke defeat Uzumaki Naruto once in a practical test.

Reward: Genjutsu: Unknown Fire.

Accept?

Kitazawa blinked. 'A mission trigger? Of course it's you.'

His first thought was whether this would disrupt his plans—but on second thought, it fit perfectly. If Sasuke tasted victory once, he'd grow overconfident. Then, when he inevitably lost during the Student Council selection practical, the emotional blow would hit twice as hard.

The real question was 'Could Sasuke actually beat Naruto now?'

The answer… was yes, there was hope. Before Naruto learned Rasengan, a Sasuke trained in the Shadow Clone Jutsu—with the right guidance—could manage it.

"Let's begin," Kitazawa said firmly.

And just as expected, Sasuke grasped the technique faster than Kiba had. Kitazawa estimated that with focus, Sasuke could master it within a week.

Time slipped by, and soon noon had arrived. After lunch, Kitazawa sent Sasuke and Hinata off for their nap before leaving the academy himself. Though the Student Council selection practical was still half a month away, he planned to meet Fugaku and his family now. Ninja were always sent on missions—some lasting days, others months. By securing their promise early, they could clear time in advance.

The Uchiha compound was familiar ground to Kitazawa. He soon reached Sasuke's house and knocked on the door.

But instead of Uchiha Mikoto, it was a girl around twelve or thirteen who answered. Kitazawa froze.

'Who? Mikoto doesn't have a daughter…'

"Are you looking for Aunt Mikoto?" the girl asked, studying him with polite curiosity.

"Yes," Kitazawa nodded, introducing himself. "I'm Sasuke's teacher, Kitazawa."

Her face brightened. "You're Kitazawa-sensei? Itachi mentioned you once. He doesn't usually talk about shinobi from outside the clan."

A name surfaced in Kitazawa's mind even before he asked. "And you are?"

"Uchiha Izumi," she replied with a smile.

'I thought so', Kitazawa mused.

In the original timeline, Izumi had been Itachi's classmate, gentle and kind, one of his few close friends. Half-Uchiha by birth, she and her mother had only returned to the clan after her father's death. She would later awaken the three-tomoe Sharingan on the very night of the Uchiha massacre… a genius in her own right, and a girl who had once confessed her feelings to Itachi—only to be quietly turned away.

"Who is it, Izumi?" Mikoto's voice floated from inside.

"It's Kitazawa-sensei," Izumi called back.

Mikoto appeared moments later, smiling warmly. "Kitazawa-sensei! Please, come in."

Kitazawa offered a polite greeting before stepping into the living room. Izumi quickly set tea before him, and he thanked her with a nod.

"Visiting at noon—was there something urgent?" Mikoto asked. "If it's important, I can summon Fugaku immediately."

Kitazawa caught the nuance. In the past, Mikoto wouldn't casually interrupt her husband's work. Fugaku was both clan head and commander of the Konoha Police Force; his time was precious. The fact that she would now call him on Kitazawa's behalf was a subtle reminder of his elevated status.

"It's not urgent," Kitazawa assured her, then revealed his purpose. "I'd like to invite your family to attend the Student Council selection practical. Lord Hokage himself will be present."

"Of course." Mikoto nodded instantly. "If the Hokage is attending, we'll certainly be there."

Kitazawa pressed gently. "It would mean a great deal to Sasuke if both his father and brother could come. He often tells me how much he longs for their recognition."

"That child…" Mikoto's smile softened. "I'll make sure to tell them."

"Can I go too?" Izumi asked suddenly, her eyes shining. The mention of Itachi's attendance had sparked her interest.

"Naturally," Kitazawa said with a faint grin. "The practical is one of the Academy's grandest events. The more spectators, the better."

"In that case, perhaps I'll inform the clan as well," Mikoto added thoughtfully. "Those who are free may also attend."

Kitazawa's brow twitched. 'Sasuke, don't blame me for this. Your mother's the one turning it into a clan affair.'

He simply inclined his head. "That works too."

Mikoto tilted her head. "Would you like to stay for lunch?"

"I've already eaten," Kitazawa replied, then paused. His gaze flicked toward Izumi. "Tell me, Izumi—are you a genin yet?"

"Yes," she nodded.

"Then… would you be interested in joining next month's Chunin Exams?"

"Huh?" Izumi blinked, startled.

Kitazawa explained the situation. But before Izumi could finish her hesitant protest, Mikoto cut in with a smile.

"If it's Kitazawa-sensei's invitation, you should accept. Izumi hasn't been assigned a squad or leader anyway."

--------------------------------

AN: Check out my P@treon For +40 extra chapters.

Thank You For your Support!!

[email protected]/noviceauthor777