Yuya's physical age was gradually approaching eight, which meant he was finally suited for this kind of hellish training.
Over the course of a month, his strength had increased somewhat—but the greater improvements were in stamina and endurance.
Back at home, Yuya estimated that if things continued this way, these basic exercises would soon stop being effective.
When that happened, he would have to begin weighted training.
The ninja world possessed extremely advanced training tools. In the original timeline, the seemingly inconspicuous metal weights Rock Lee wore were terrifyingly heavy.
But when Yuya thought of how Uchiha Sasuke later used lightning-based stimulation to enhance his body and catch up to Rock Lee's speed in just a month, he couldn't help feeling a little envious.
If only I could find a training method that truly suits me…
Exhaling, Yuya cast those thoughts aside and rested briefly before resuming his workout.
At home, he trained without restraint—
pushing himself into limit-breaking training.
So-called limit training meant draining every last ounce of strength from the body, forcing it to collapse, then surpassing that collapse.
As training accumulated, Yuya's body gradually developed clearly defined muscles.
However, this was only the first stage.
In the ninja world, muscles alone meant very little.
As training continued, those muscles would fade, then reappear—refined, smooth, and fully integrated.
That stage marked the body's true completion.
Based on the ninja world's accelerated physical development, Yuya estimated this would occur somewhere between fourteen and sixteen years old.
But that was only if he survived that long.
In less than two years, the Second Great Ninja War would erupt.
Yuya remembered that clearly.
As his training progressed, the power of his vibration force had also increased. Against weaker C-rank ninjutsu, he might already be capable of shattering them outright.
Of course, even among C-rank techniques, the difference between a chūnin, a jōnin, or a monster like Uchiha Madara using them was enormous.
Ninjutsu was vast and profound—
But so were taijutsu, and Yuya's Vibration Release Kekkei Genkai.
If developed to the extreme, it might truly be capable of shattering space itself.
Sweat dripped steadily onto the floor.
His arms were almost completely rigid now—he was continuing purely through willpower.
He had already surpassed his previous limit.
Yet Yuya's face showed nothing but resolve. Gritting his teeth, he forced himself onward, pushing dozens of repetitions beyond last time before finally collapsing, utterly unable to rise.
Yuya treated his training with ruthless severity.
He had no choice.
Without desperation, how could he hope to survive the Second Great Ninja War?
A backgroundless outsider like him would undoubtedly be sent to the most dangerous frontline missions once war broke out.
Kushina was different.
She was Konoha's designated next Nine-Tails jinchūriki. Once war truly began, she wouldn't be sent to battle at all—she likely wouldn't even be allowed to leave the village, guarded with extreme vigilance.
Yuya wasn't worried about her safety.
The only person he had to worry about—
Was himself.
Suddenly, the sound of a key unlocking the door rang out.
Yuya looked toward the entrance in surprise, trying to prop himself up—but his body hadn't yet recovered from reaching its limit.
There was only one person he trusted enough to have his house key.
"You really worked yourself into this state again…"
Kushina entered, carrying dinner. She sighed helplessly at the sight of him, then helped him up without caring about the sweat covering his body.
"I seriously don't get it. You've already awakened that Vibration Release Kekkei Genkai and become so strong—why push yourself this hard?"
Her cheeks puffed slightly as she looked at him in confusion.
Yuya thought for a moment.
He chose not to tell her about war, bloodshed, or the darkness ahead.
Instead, he smiled.
"Because there are still people stronger than me."
"…Minato Namikaze?" Kushina pouted. "You know it won't be easy to surpass him."
"Exactly," Yuya replied with a smile.
"That's why it's worth pushing myself."
Kushina snorted softly, then broke into a smile.
"I believe you'll surpass him someday."
"Yeah."
Yuya nodded, then scratched his head awkwardly.
"By the way… could you lend me some money?"
"Huh?"
Kushina looked at him in surprise. "Of course… what for?"
"Uh—training tools. Ninja equipment," Yuya said sheepishly.
"My funds are basically all gone."
As an orphan, Yuya was supposed to receive village assistance.
But because he was from outside Konoha, most of it was withheld. What remained barely covered food.
There was nothing he could do about it—except grow stronger and escape this situation himself.
"Those people are really…"
Kushina clenched her fists angrily, then sighed and patted Yuya's shoulder.
"Alright. I'll lend it to you."
"I won't be able to pay you back right away," Yuya said apologetically.
"But once I become a genin and take a few missions—"
"If you plan on paying me back, then I won't lend it," Kushina cut in, pouting.
"..."
Yuya sighed helplessly. "Alright, alright… I'll make it up to you in other ways."
"Hmph."
Kushina gave an exaggerated, tsundere snort, handed over the money, and left.
Looking at the dinner she'd prepared, Yuya's gaze softened.
"…At this rate, I really might change the original timeline completely."
"But there's no way I can just ignore Kushina's feelings."
Later, walking through the streets of Konohagakure, Yuya looked around, smiling faintly.
Everything still felt unreal.
Yet he truly was here—
in the Naruto world, in Konoha.
Though he had lived here for a long time, he had been so focused on training that he'd barely noticed the village's bustling streets.
After wandering for a while, Yuya arrived at a ninja tool shop.
Just as he was about to enter, he suddenly paused.
"…Huh?"
He saw a familiar figure.
A green jumpsuit.
Thick eyebrows.
But Rock Lee hadn't even been born yet—and Might Guy, even if he existed, would still be a child.
Which meant—
Yuya instantly recognized him.
The man buying weighted training gear was none other than—
Konoha's eternal genin… Might Duy.
The father of Might Guy.