Naruto: Strongest Shinobi System With a Glitch

Kitazawa had one fewer class today than he’d had yesterday.

The morning lesson was Will of Fire, while the afternoon was devoted to practical combat training.

After finishing his morning class, Kitazawa returned to his office. 𝐟𝕣𝗲𝕖𝕨𝗲𝐛𝗻𝗼𝐯𝗲𝚕.𝗰𝚘𝐦

He casually picked up the stack of homework on his desk and began flipping through the pages.

There was no homework assigned for practical combat, only for Konoha History and Will of Fire.

The assignments for those two subjects weren’t particularly difficult, and everyone had passed, with a few students turning in work that was surprisingly impressive.

To Kitazawa’s astonishment, Uzumaki Naruto was among those top performers.

’Looks like my teaching’s paying off,’ Kitazawa mused.

And it wasn’t empty pride—after all, in the original timeline, Uzumaki Naruto had been dead last in his class.

Dead last meant utterly hopeless, both in theory and in practical combat—a total mess.

Soon, it was time for the final period of the day: practical combat class.

"Today, we’re continuing with kunai throwing."

Standing before his students, Kitazawa addressed them. "Anyone who hasn’t mastered it yet should keep practicing. Those who already have can use the time however they like."

A ripple of surprise went through the class, especially among the ninja clan prodigies like Uchiha Sasuke and Nara Shikamaru.

After all, free time was practically the same as canceling class altogether.

"Damn it! I totally miscalculated!"

Kiba let out a wail, freezing in place like a statue. "If I’d known this would happen, I would’ve shown my real skills yesterday!"

"I’m definitely hitting the bullseye today!"

Naruto clenched his fists in determination.

He’d already earned a snack reward from Kitazawa yesterday, and if he failed again today, it’d be way too embarrassing.

Meanwhile, Hinata cast a shy glance toward Kitazawa.

After a moment’s thought, she decided to stay behind and keep practicing her kunai technique—even though she’d already mastered it long ago.

"This sensei’s really something... I like him," Shikamaru murmured.

He promptly found a patch of grass, lay down, and used his hands to prop up his head, getting comfortable under the afternoon sun.

"Totally," agreed Choji, plopping down beside him and tearing open a bag of chips, the crunch echoing in the training ground.

"Sasuke-kun!"

Sakura rushed over to Sasuke. "Will you show me that curving kunai throw from yesterday?"

"I don’t have time."

Sasuke shut her down without even glancing in her direction, striding away toward the far end of the training grounds.

Once there, he began forming hand seals.

’Fire Release: Great Fireball Jutsu’

Chakra flared around him, then condensed into a blazing, fist-sized fireball that hovered in the air before sputtering out.

Disappointment flickered across Sasuke’s features.

Everyone said he was a genius—but compared to his older brother, Itachi, he felt painfully mediocre.

Itachi had mastered the Great Fireball Jutsu perfectly after seeing it only once. Sasuke, on the other hand, was still struggling.

"Why can’t I do it...?"

Sasuke clenched his fists, teeth gritted.

He wanted so badly to learn it—to earn the praise of his father and brother.

Just imagining such a scene made the corners of his mouth twitch upward in a fleeting smile.

But for now, it was nothing more than a fantasy.

"Your chakra control needs work."

A voice cut through his thoughts.

Sasuke turned sharply to see Kitazawa standing nearby.

For a split second, Sasuke froze. His eyes flickered with surprise, quickly masked by his usual cool indifference.

’What would a mere Chunin instructor know about the Great Fireball Jutsu?’

Kitazawa wasn’t an Uchiha. He couldn’t possibly understand the intricacies of their clan’s techniques.

"Come with me," Kitazawa said firmly.

He could read Sasuke’s thoughts as if they were written on paper.

He wasn’t offended—after all, he knew how proud the Uchiha Clan could be.

But this was the perfect opportunity to complete one of his system’s missions. And he wasn’t about to let it slip away.

"Where are we going?"

Sasuke eyed Kitazawa with suspicion as they walked.

"You’ll see soon enough," Kitazawa replied, a faint smile on his lips.

He led Sasuke to a secluded training ground behind the academy buildings.

Just as Sasuke opened his mouth to ask another question, his eyes went wide at the sight unfolding before him.

’Fire Release: Great Fireball Technique’

With a deep breath, Kitazawa unleashed a massive fireball. Flames roared from his lips, growing into a blazing sphere far larger than any Sasuke had ever seen—even larger than the one his older brother had demonstrated.

Sasuke stood frozen, his mind blown. This completely shattered his understanding of who Kitazawa was.

"Want to learn it?" Kitazawa asked, chuckling at Sasuke’s stunned expression. "I can teach you."

Although the Great Fireball was a signature jutsu of the Uchiha Clan, it wasn’t exactly a forbidden secret. Because it was powerful yet relatively simple to learn, many non-Uchiha ninja had picked it up over the years—including Kitazawa’s late squad leader.

Thanks to that, Kitazawa wasn’t worried about anyone questioning the source of his technique.

It took Sasuke a few moments to recover his voice.

’If I could pull off a fireball that huge... my father and brother would definitely see me differently.’

"Kitazawa-sensei, I want to learn!" Sasuke declared, his eyes blazing with determination.

Unlike in the original timeline, this Sasuke wasn’t quite as withdrawn yet, so he wasn’t shy about asking.

Kitazawa nodded, pleased. "To master the Great Fireball Jutsu, you have to work on two things: chakra control and chakra nature transformation."

In the original series, the details of training for Fire Release weren’t fully explained—but there was a clear precedent in how Wind Release nature transformation was taught. Naruto had learned it from Asuma Sarutobi:

First step, slice a leaf.

Second step, cut a waterfall.

Third step, channel the nature transformation into actual jutsu.

"Chakra nature transformation is a bit too advanced for you right now," Kitazawa continued. "So let’s focus on improving your chakra control first."

He pointed to a tall tree nearby.

"Channel chakra to the soles of your feet, and climb that tree. Simple as that."

The Great Fireball Technique technically involved a bit of shape transformation, too—but it was only a C-rank jutsu. Unlike the Rasengan, it didn’t require advanced shape manipulation—just enough to make the flames big and round.

"That’s it?" Sasuke frowned, skeptical.

"Go on. Try it."

Kitazawa smirked, remembering that even in the original story, Sasuke hadn’t nailed this exercise on his first attempt—despite already being a graduate then. Now, as a newly enrolled student, his chances were even slimmer.

"Watch me do it in one shot!" Sasuke snorted and marched toward the tree.

Focusing chakra to his feet, he stepped onto the trunk and began ascending.

"See? Easy."

Sasuke smirked as he took two steady steps upward. But pride always came before a fall—literally.

Halfway up, he lost his footing, and with a startled yell, he crashed to the ground.

"How’d that go for you?" Kitazawa teased, folding his arms.

"It... it was the tree bark—it’s too slippery!" Sasuke protested, cheeks flushed red.

Grimacing, he climbed to his feet, took a deep breath, and prepared to try again.

[Current Mission: Earn the initial approval of your classmate, Uchiha Sasuke.]

[Mission Reward: Fire Release: Phoenix Flower Jutsu]

[Mission Complete. Reward granted.]

Kitazawa arched an eyebrow as the familiar system message flashed across his vision.

’Tsundere is definitely out of style these days...’

A flood of new information rushed into his brain as the reward data integrated itself seamlessly into his memory.

Glancing back at Sasuke, who was now doggedly climbing the tree again, Kitazawa frowned in thought.

’How should I explain having a new jutsu from the system?’

Low-level jutsu could be chalked up to lessons from his deceased squad leader or teammates. Dead people were pretty handy—they couldn’t contradict your story.

But higher-level techniques, especially B-rank and above, couldn’t be brushed off so easily.

In the ninja world, there were only two recognized ways to gain new jutsu: either learning it directly from a sensei or being granted it as a reward from Konoha’s leadership.

Kitazawa stroked his chin, pondering.

[Your lifelong rival, Uchiha Sasuke, is training hard to master Fire Release. You can’t fall behind.]

[New Mission: Master a C-rank jutsu faster than Uchiha Sasuke.]

[Reward: Manipulating Shuriken Technique.]

[Do you accept?]

A new line of system text flickered before his eyes.

Kitazawa blinked, speechless.

’For a regular chunin like me to be set up as Sasuke’s lifelong rival... this system really doesn’t hold back.’

While he was glad for a new mission, this one wasn’t as easy as it sounded.

’I don’t even have a new C-rank jutsu to train. Even if it’s "just" C-rank.’

He considered whether to approach Hiruzen Sarutobi for a scroll.

But then he sighed, massaging his temples.

’I’ve got no merits to my name yet. Just barging in and asking for a new jutsu would look suspicious.’

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