Naruto: Life as Kagami Uchiha (AU)

"Hiss—"

"Kagami, did you really kill Chiyo?!"

Sakumo Hatake walked over, his face filled with disbelief. "She was said to be the wife of the First Kazekage, a highly respected figure in Sunagakure with extraordinary strength. And you took her down effortlessly? You didn't even bother using your Mangekyō Sharingan?"

"It's not that I was too lazy to use it—it was simply a matter of caution."

Uchiha Kagami explained, "Do you think that White Secret Technique just now was easy to deal with? That overwhelming pressure would have been difficult to counter, even with the Mangekyō. So, I chose the most reliable secret technique—not only did it neutralize her attack, but it also eliminated her."

"What kind of secret technique? Something stronger than the Mangekyō?"

"The Spirit Transformation Technique."

"Huh? Isn't that Kato Dan's signature jutsu? How did you learn it?"

"I sparred with him a month ago and learned it from him. Kato-san is a decent person—he didn't mind me using it."

Kagami wasn't lying.

To ensure that he could use the technique openly, he had recently engaged in friendly sparring matches with some of Konoha's Jōnin, using a few B-rank jutsu as an exchange. This allowed him to "officially" acquire and be authorized to use their unique techniques.

Never underestimate B-rank jutsu.

Because of the hierarchical structure of the ninja world, civilian shinobi had extremely limited access to jutsu. Even if they wanted to learn, opportunities were scarce.

Do you think civilian ninja don't want to learn more techniques?

Anyone with talent would love to master as many jutsu as possible. Even geniuses like Sakumo Hatake faced the same dilemma—not because he didn't want to learn more, but because he had no place to learn from.

As a result…

In his spare time, he devoted himself to swordsmanship.

And with his self-created "Hatake Sword Style," he killed Sasori's parents, earning the feared title "Konoha's White Fang." Kato Dan was in a similar situation—he just died before he could make a name for himself.

Of course, there were other ways to learn jutsu.

Exceptionally talented shinobi could find a mentor—for instance, the soon-to-be-legendary "Three Sannin of Konoha."

Tsunade was from the Senju Clan, which speaks for itself. But both Jiraiya and Orochimaru came from civilian backgrounds. By becoming Hiruzen Sarutobi's students, they broke free from the constraints of the shinobi hierarchy and learned countless high-level jutsu.

Even so, B-rank jutsu were already at Jōnin-level difficulty.

On the battlefield, one extra jutsu meant one more chance at survival. With no other options, Kato Dan and the others were actually grateful to Kagami—they saw the trade as fair.

But the Spirit Transformation Technique?

No, this wasn't just some secret technique anymore.

It was forbidden jutsu—an unquestionable, S-rank forbidden jutsu!

Because this was the only jutsu in the entire shinobi world that directly affected the soul.

It allowed the user to separate their spirit from their body, transforming into an ethereal form that could invade an enemy's mind, causing their consciousness to collapse and killing them instantly.

Of course…

That was only the most basic way to kill.

Since the spirit retained the user's will, it didn't need any medium to infiltrate the target. This meant it could force the enemy into a brief or prolonged state of unconsciousness.

That was the true horror of the Spirit Transformation Technique!

Even the Sharingan's genjutsu relied on eye contact to channel chakra into the opponent's brain, acting through visual stimuli.

Other genjutsu, like Fukasaku and Shima's "Demonic Illusion: Toad Confrontation Chant" or Tayuya's "Demonic Flute: Phantom Sound Chains," required auditory input to invade the mind.

All genjutsu depended on at least one of the five senses to activate.

But the Spirit Transformation Technique was different.

Physical attacks were useless against a spirit form—there was no way to defend against it.

And the spirit's speed was unbelievably fast.

Before Chiyo could even react, Kagami instantly killed her.

Moreover…

A spirit form could sense souls.

No matter the distance, even without knowing the target's location, the user could reach them in an instant. They could also use the jutsu to remotely confirm a target's life status or communicate across distances.

As for why Kato Dan died young?

The reason was simple…

Chakra.

Most civilian shinobi had very little chakra.

A rare exception was someone like Naruto, who could summon thousands of shadow clones. But Kato Dan, despite being a Jōnin, probably had at most 2,000 chakra points.

The Spirit Transformation Technique didn't consume an absurd amount of chakra, but it was still significant.

During the Second Shinobi War, Kato Dan had very little chakra left on the battlefield. Without enough chakra to sustain long-range kills, his defenseless physical body became his greatest weakness.

It was only natural that his enemies took advantage of that opening.

As for the Fourth Shinobi War?

If not for Kabuto, the "Dream Fulfillment Ambassador," supplying him with unlimited chakra Wi-Fi, Kato Dan's spirit wouldn't have been able to cross the battlefield in time to save Tsunade from Madara.

That said, the full potential of the Spirit Transformation Technique remained untapped.

With the right research, it could be combined with the Sharingan to develop even more terrifying abilities.

But for now, it wasn't necessarily stronger than the Mangekyō Sharingan.

After all, at that moment, there hadn't been time to activate the Mangekyō.

And before obtaining the Eternal Mangekyō, using it too much risked blindness. So avoiding overuse was wise.

As for Flying Thunder God?

Keeping it hidden as a trump card made sense. Given the other jutsu at his disposal, there was no better way to counter Chiyo's "Three Treasures Suction Crush" while also ensuring a lethal strike.

But one thing was clear…

Whether it was Sakumo Hatake, who killed Sasori's parents, or Uchiha Kagami, who eliminated Chiyo…

Both were young prodigies in their twenties, destined to no longer be obscure figures.

Kagami, already an accomplished warrior, would rise to even greater prominence.

"Kagami, should we head back now?" Sakumo asked.

"I don't think it's time yet."

"Kagami…"

After a moment of hesitation, Sakumo said, "You and I have achieved enough merit. Chiyo's death is a great advantage for Konoha, but she held a very high status in Sunagakure. This could enrage the Third Kazekage."

"Not to mention, there are still plenty of Suna's advance forces nearby. Shouldn't we return to the village and report to the Hokage before making our next move? The Hokage hasn't given any further attack orders. What do you think?"

"But Sakumo… war is unpredictable."

Kagami's eyes burned with determination. "For us personally, we've gained enough merit. For Konoha, the battle is in our favor. But it's not enough.

We need a decisive victory.

If Chiyo's death will enrage the Third Kazekage… then let's use that to our advantage. Let's annihilate the remaining Suna forces—but deliberately let some escape to spread the news.

And then…

We assassinate the Third Kazekage.

What do you think?"

(Note: At this time, in Konoha Year 37, Rasa was only 15 years old and not yet the Kazekage.)

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