Yoruha continued, calmly explaining,
"Right now, Naruto has two Eight Trigrams Seals inside him. The Fourth's original Eight Trigrams Seal now mainly serves to convert a portion of the Nine-Tails' chakra into Naruto's own."
"The sealing function itself isn't very stable. Even though I reinforced it, as long as Naruto keeps using the Nine-Tails' chakra, it'll loosen again over time."
"If we left it like that, I'd have to keep reinforcing it again and again. That would be way too troublesome."
"So I decided to add a second Eight Trigrams Seal. The new one's primary purpose is to stop the Nine-Tails from actively sending chakra to Naruto."
"And I didn't leave any intentional gaps in it."
"The sealing strength is also much higher. As long as Naruto doesn't deliberately undo it, the Nine-Tails has no way of breaking through on its own."
"And the Fourth's original Eight Trigrams Seal stays in place, mainly handling the chakra conversion."
"My Eight Trigrams Seal is primarily responsible for sealing the Nine-Tails and making sure that, as long as Naruto doesn't actively unlock it, the fox will stay sealed safely."
Kakashi nodded.
"In that case, this really is ideal. I can feel how strong the seal you left is."
Yoruha nodded back.
"To put this seal in place, I burned through all of my chakra. Of course it's strong."
Kakashi frowned sharply.
"Your chakra was completely drained?"
"Why are you always taking things this far?"
He really didn't want Yoruha pushing himself to the limit every single time.
For a shinobi, running out of chakra carried the risk of death.
That much would become painfully clear years later, when Kakashi used Kamui to save Chōji and died on the spot from overexerting his chakra.
He hadn't experienced that yet—but he still understood the principle.
Right now, he was honestly a little angry.
Yoruha was simply too reckless.
Yoruha gave him an awkward smile.
"My recovery ability is pretty good, though. Look, I'm fine now, aren't I?"
Kakashi said seriously,
"Yoruha… I need to teach you something from experience as a shinobi. In battle, you absolutely cannot use chakra without limit."
"As a proper ninja, you should constantly be aware of your reserves. When your chakra gets too low, you need to start thinking about abandoning the mission."
That bit of advice clearly didn't match the official shinobi rules.
According to those, the mission came first.
If necessary, a shinobi was expected to sacrifice their life to complete it.
Yoruha had learned those rules too.
But he didn't argue with Kakashi. He simply nodded.
"I understand, Kakashi-sensei."
Kakashi patted him on the shoulder.
"You've already done a lot for Naruto. But I don't want you getting hurt someday because you let your guard down."
"Remember this—only geniuses who live long enough to grow are truly geniuses. A genius who dies early is just a name people forget."
He would never say that to just anyone.
Those words ran counter to the official doctrine of the shinobi world.
But Kakashi didn't want Yoruha to die before he fully bloomed.
He'd seen that tragedy far too many times.
There were plenty of geniuses in the ninja world—
but most died before ever reaching the level of Hashirama or Madara.
Yoruha nodded again.
Before long, Sakura and Sasuke arrived as well.
Seeing Naruto lying unconscious on the bed, Sakura asked anxiously,
"Yoruha, Kakashi-sensei, how's Naruto?"
"He's fine," Yoruha replied. "He just passed out because a large amount of the Nine-Tails' chakra surged out earlier. It's already under control now."
Sasuke looked at Yoruha and frowned slightly.
"You finished?"
Yoruha nodded.
"Yeah. It's done."
"Looks like your sealing techniques are finally practical," Sasuke said coolly. "At least this idiot won't go on a rampage with nobody able to stop him anymore."
That was just his usual way of speaking.
Yoruha looked at him and smiled.
"I'd actually rather you finish developing your Sharingan. That way, even if the Nine-Tails does break free someday, your eyes could control it."
Sasuke froze.
Then he replied in his usual cold tone,
"Who knows if I'll ever get that strong."
The words sounded distant and aloof—
but the lack of confidence was obvious.
After spending so much time around Yoruha, watching his strength rise again and again, Sasuke couldn't help feeling inadequate.
They were the same age, yet the gap between them was enormous.
Sometimes, he even wondered if Yoruha might already be stronger than Itachi.
Of course, that was just his own guess.
If someone told Yoruha to go challenge Uchiha Itachi right now, Yoruha himself wouldn't dare.
Not because he feared Itachi's ninjutsu—
but because he had absolutely no confidence against the man's Mangekyō Sharingan.
Yoruha knew perfectly well that Itachi had dropped Kakashi in an instant with just Tsukuyomi.
Even Orochimaru had been helpless before him.
His body might've been frail, but those eyes were terrifying.
If Yoruha ever crossed paths with Itachi, his first thought wouldn't be how to defeat him—
It would be how to survive long enough to escape.
Not cowardice—just a clear understanding of reality.
There was no point in a meaningless fight.
Whether Yoruha could actually beat Itachi was anyone's guess.
But he had no confidence in it yet—and had never once considered fighting Itachi at his current level.
To him, Itachi's most frightening strength wasn't Susanoo, Amaterasu, or any Mangekyō sealing arts—
It was his genjutsu.
Until he had a reliable countermeasure, if Yoruha ran into Itachi, running would be the smart move.
He could hear the insecurity in Sasuke's voice and grinned.
"What, you don't have any confidence?"
Sasuke shot him a glare.
"I'll surpass you. Definitely."
"I'll be waiting," Yoruha said, still smiling. "But you'll need to fully develop your Sharingan first. At the very least, you'll need to reach Kakashi-sensei's level."
Sasuke glanced at Kakashi, expectation flickering in his eyes.
Which made Kakashi feel a headache coming on.
From now on, Sasuke was probably going to cling to him.
And as his teacher—and someone who did have experience developing the Sharingan—Kakashi knew he couldn't brush Sasuke off.
Otherwise the boy would end up thinking he was playing favorites.
Then again…
maybe this was good.
He'd originally planned to focus on teaching Yoruha.
But in less than two months, Yoruha had already learned every jutsu Kakashi intended to teach him.
Aside from anything related to the Sharingan, Kakashi had nothing left to offer the boy.
Now, he could finally focus more on training Sasuke, Naruto, and Sakura.
He could finally do his actual job as a jonin instructor.
So Kakashi nodded and promised,
"I'll teach you how to control your Sharingan. If I'm not mistaken, you've already awakened to the two-tomoe stage, right?"
Sasuke nodded.
"One eye with two tomoe. The other still only has one."
"Not bad," Kakashi said. "For your age, that's already impressive."
If he remembered correctly, Obito had awakened his two-tomoe Sharingan around thirteen.
Of course, what Kakashi didn't know was that around the same age, Obito had also awakened the Mangekyō.
Not that awakening the Sharingan early automatically made someone stronger.
Even Uchiha Madara had awakened his first tomoe at fifteen.
Sasuke had awakened his at six—
only because the trauma he'd endured had been far too great.
At that age, his body had only just barely been capable of handling a single tomoe.
Now, one eye had advanced to two tomoe and the other to one, triggered when he saw Naruto collapse in front of him.
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