10- I will not allow it.

The Uzumaki were the masters of fūinjutsu. Their village had been destroyed, in part, because of their knowledge. If this seal truly existed, it could change a great many things.

He carefully reread the instructions. The seal was designed to increase the density and quantity of chakra refined by the user. A complex process that involved redirecting the flow of chakra through a network of symbols engraved on the skin. Once activated, it would allow the user to produce more chakra, more quickly, with less effort.

But if I modified it?

His thoughts drifted toward another universe. Another manga he had read and loved in his previous life. Jujutsu Kaisen. And the character of Gojo Satoru, with his ability to render his energy consumption infinitesimal.

If I could adapt this seal so that it made my chakra consumption almost zero…

He smiled. The idea was bold, almost ridiculous. But if it worked, he would have nothing left to envy a bijū. A near-inexhaustible reserve of chakra, without the risks of a demon sealed inside him.

Yet raw power and endurance did not solve everything. Minato raised his eyes toward the treetops, his smile fading to make way for a contained gravity.

There was a category of threats against which neither speed nor power served much purpose.

Genjutsu.

The image of Shisui Uchiha formed in his mind. Kotoamatsukami. A Mangekyō Sharingan capable of forcing the will of anyone without the victim even realizing it. A technique that usurped the mind, that rewrote thoughts. And then there was Itachi. Tsukuyomi, the world of lunar arcana, where time and suffering were controlled by the bearer, capable of breaking a man in a fraction of a second in reality.

And later, much later, the Infinite Tsukuyomi. The mass illusion.

Minato clenched his fists. How does one defend against an attack that manipulates the flow of chakra in the brain before one can even blink? The speed of the Hiraishin was useless if the illusion took root in an instant.

He thought back to fūinjutsu. If he could manipulate the density of chakra, could he create a defensive seal? A barrier anchored in his own network that would detect the disturbance of a foreign chakra attempting to infiltrate his cortex? A kind of automatic energetic antidote.

The more he reflected on it, the more the evidence imposed itself. Fūinjutsu was not a simple tool. It was the keystone of his survival, and by extension, of Konoha’s. It was the solution to the gaps impossible to fill through physical training.

He knelt near the stump and took out a brush and a pot of ink from his bag. He dipped the fine bristles into the black liquid.

The wind had freshened. The leaves rustled above his head, casting moving shadows on the ground. He inhaled deeply, smelling the scent of earth and moss.

For the first time since his arrival in this world, he felt he had a direction.

I will become the master of fūinjutsu.

If before, as a fan, he had believed it, now he had the certainty: fūinjutsu was the most powerful, the most versatile, the most underestimated art of the ninja world. It could seal demons, contain catastrophes, protect entire villages. And it could do far more still, in the hands of someone who understood its true potential.

He smiled.

I will make this world a place where my own and I can live in peace. Even if I have to rewrite everything to get there.

***

At the mission assignment office, Minato pushed open the swinging door and was immediately seized by the effervescence that reigned in the hall. A cacophony of voices crossed above the worn wooden counters, where shinobi of every rank jostled to deposit their reports or claim their assignments. Mission scrolls piled up in unstable towers on the clerks’ desks, threatening to collapse at the slightest draft. At the back of the room, a rotating fan tried in vain to stir the confined atmosphere, producing a regular clicking that was lost in the hubbub.

He had barely taken three steps inside when a voice called out to him.

“Minato-san!”

He turned.

Takeda was making his way between two groups of chūnin, a brilliant smile plastered on his face. His Konoha forehead protector was set askew on his brow, as always.

Behind him came Kyōya, then Tsubaki, a short-haired kunoichi who wielded the tantō with surgical precision. And finally Gorō, the big strong one.

The team he had extracted from hell a week earlier.

“Are you well?” Minato asked, a polite smile on his lips.

Takeda approached and held out his hand—a frank, vigorous handshake that squeezed a little too tightly.

“Better than well, thanks to you. We came back without a single additional loss.”

Minato nodded.

“And Takemichi?” he asked. “How is he?”

Takeda’s smile lost a little of its brightness.

“The doctors say he’ll walk again. His arm, though…” He shrugged. “The nerves were severed. Surgery saved the function, but he’ll lose a third of his mobility.”

Minato remained silent a moment.

If I hadn’t taken possession of this body, maybe he… No, that’s not the right way to think.

“I’ll go see him.”

Takeda nodded. Then his expression changed, sliding toward something lighter, almost teasing.

“By the way, we heard a rumor when we arrived. You’ve been pulled from the front?”

Kyōya, behind him, raised an eyebrow.

“Has command lost its mind?” he said in a drawling voice. “We’re depriving the village of its most profitable weapon to put it where, exactly?”

Minato crossed his arms.

“The Hokage assigned me a team.”

Gorō burst out laughing.

“A team? You? Sensei?” He held his sides as if the very idea were physically painful. “The guy who dispatches twenty enemies in three seconds is going to have to teach kids how to throw shuriken?”

Tsubaki, who had remained silent until then, let out an amused breath.

“I give him three days before he starts talking about withdrawal strategy to ten-year-old children.”

Minato smiled.

Takeda looked at him for a moment, his smile softening.

He held out his hand a second time. “Good luck, then.”

Minato shook the hand. Takeda turned toward the others.

“Let’s go. We leave again at dawn tomorrow. Reinforcement detachment on the Shimogakure line.”

Kyōya threw him a glance over his shoulder.

“Don’t be too hard on the kids, Minato. Even you had to start somewhere.”

They disappeared into the crowd, their silhouettes blending among the other shinobi who peopled the hall. Minato watched them move away.

May they all come back.

He turned and advanced toward the central counter.

On the way he crossed other familiar faces. No—familiar was not the word. These faces appeared on no page of the manga, no episode of the anime, no databook edition. And yet Minato’s body recognized them.

A woman with gray hair tied in a bun, seated behind a desk overloaded with documents.

Yamanaka Kei.

Secretary of the assignment office for fourteen years. She wore round glasses that gave her a severe air, but the smile she addressed him was warm.

“Namikaze-san. Congratulations on your new assignment, by the way. The village is already talking about it.”

Farther on, a massive man with a shaved skull blocked the passage while discussing with a group of chūnin.

Raiken.

An acquaintance from the Academy with whom they had shared missions.

He gave him a respectful nod as he passed.

None of these details figured in the manga.

None of these faces had been drawn by Kishimoto.

And yet they were there. Real, tangible, with their stories and their wounds and their lives that continued beyond the pages he had read.

Minato pushed the exit door and emerged into the outer corridor.

That was where he saw him.

Kakashi Hatake was seated on a wooden bench, leaning against the wall of the administrative building. His legs, too short to touch the ground, dangled in the void. His arms were crossed over his chest—a defensive gesture, almost comical on a child of that age, yet one that betrayed a posture Minato recognized immediately. The boy wore his Konoha forehead protector like a badge, not an accessory. Straight, centered, impeccable. His chūnin uniform was new, without a crease. The black cloth mask covered the lower half of his face, leaving only his eyes visible—gray eyes, calm, and of a hardness that no child of that age should have possessed.

Minato stopped for a moment. In the manga, child Kakashi was already a prodigy. Graduated from the Academy at five, chūnin at six. A genius forged in solitude and the contempt of others, marked by his father’s suicide and the social rejection that had followed.

He who is going to lose so much…

Minato clenched his teeth. The expression lasted only a fraction of a second—he chased it away, replaced a mask of calm on his features.

I will not allow it.