Shinigami in the Ninja World

Kurotsuchi Mayuri was eager and filled with anticipation.

Although there wasn't much to study about "Summoning Jutsu," and it wasn't particularly difficult, its value as a "research topic" wasn't very high.

However, through it, one could catch a glimpse of the tip of an unfamiliar and vast knowledge system.

No "scientist" could resist the thirst for knowledge.

"I have a problem," Naruto thought for a moment, then removed his hand from the book. "Please wait here for a moment."

He stood up and left. After a short while, he returned with a rabbit in his hand.

Mayuri narrowed his eyes.

Although the Soul Society was a world of the "dead," it also had a well-established ecosystem, with animals being part of it.

But a rabbit? What kind of research topic is that?

"I have placed a seal on this rabbit," Naruto placed the rabbit on the table. "A power is stored within its body."

"I would like Captain Kurotsuchi to break the seal and extract the power without harming the rabbit's life."

Just now, he had gone out and temporarily turned the rabbit into a sort of "jinchuriki."

"The life of a rabbit," Mayuri clicked his tongue. "Captain Uzumaki is truly merciful."

"However..."

"This seal, is it related to you?"

Naruto softly replied, "Captain Urahara wouldn't ask such irrelevant questions."

Mayuri clicked his tongue even louder.

"Oh, and let me remind you," Naruto tilted his head and looked at him, "I don't have much hope that you can successfully break the seal."

"After all..."

"This is something even Captain Urahara couldn't accomplish."

Mayuri's demeanor suddenly became sharp, his tone hostile: "Captain Uzumaki really trusts that man."

"If he were capable, he wouldn't have fled the Soul Society like a rat."

"Just because he couldn't do it doesn't mean I can't."

He grabbed the rabbit by its ears. "Just wait, Captain Uzumaki. But next time... what I want won't be this insignificant."

"You can come to me anytime for a new rabbit if you fail," Naruto cheerfully waved him off.

Mayuri left, exuding a fierce aura.

Watching his back, Naruto sighed.

Urahara Kisuke hadn't actually delved deeply into breaking the "Four Symbols Seal."

He had just mentioned it casually.

But, as expected, using "competition" between people could indeed stimulate a lot of motivation.

He picked up the book and began reading.

Just on the first page, Naruto sighed again. Urahara Kisuke's past evaluation was spot on—Kurotsuchi Mayuri was indeed a very intelligent and capable person.

He had modified the "Summoning Jutsu" and executed it using Kido.

The difficulty wasn't particularly high, approximately equivalent to a binding spell in the twenties or thirties.

He had also simplified the "technique," making it even more streamlined than before.

So much so that...

In the next book,

He deduced a "Reverse Summoning Jutsu" and combined it with the "Shunpo" technique, developing a method to use the "Summoning Jutsu" to "rapidly transfer within the same space." However, it had only been a year, and this technique was not yet fully perfected.

Mayuri candidly admitted in the book that this technique had flaws. Although it was a space transfer during movement, the activation time was too long, making the significance of "space transfer" minimal.

Moreover, the technique was extremely difficult to learn.

It not only required delicate control over spiritual power but also demanded a high level of reflexes.

And since Mayuri wasn't particularly interested in this power, further research would take a lot of time. He stopped there, but... he also wrote that if Naruto were interested in this technique, he could continue the research after he provided something he wanted.

Truly a man recognized by Urahara Kisuke.

These books were quite beneficial to Naruto.

The long lifespan of a Shinigami brought with it a life with few changes.

Naruto's days were spent handling squad matters and then repeatedly studying the "Four Symbols Seal" and "Reaper Death Seal."

Occasionally, Nine-Tails would complain, blaming Minato for sealing his other half, making it impossible for him to practice "Bankai" now.

Or Mayuri would come to him, with a dark expression, demanding a new rabbit.

Breaking the "Four Symbols Seal" was a very difficult task.

All the sealers needed to do was seal, but those who broke the seal had to consider many more things.

Unknowingly, the season of cherry blossoms blooming had arrived again.

Sosuke Aizen paid him a visit.

After exchanging pleasantries,

"Naruto-kun shouldn't have anything urgent to attend to recently, right?" Aizen asked.

Naruto shook his head.

"Would you like to attend the opening ceremony at the Shin'o Academy of Spiritual Arts?" Aizen extended an invitation.

Naruto was momentarily stunned as he looked out the window. "It's that time of year again, isn't it? The start of the new term."

"But why would Aizen-san invite me?"

Aizen smiled. "Naruto, you know me. I attend the opening ceremony every year."

"Every year, I hear the students talk about wanting to meet Uzumaki Naruto, the youngest captain."

"They're so eager."

"I wanted to fulfill their wish, so I came to invite you."

Naruto nodded.

The emotions reflected back through his sensory ability showed that this part of the conversation was sincere.

"Since Aizen-san put it that way, I have no reason to refuse," Naruto agreed.

Aizen lifted his head and looked out the window with him. In the courtyard of the 7th Division, a cherry blossom tree stood, its petals fluttering down like rain in the breeze. "That's wonderful, Naruto."

Suddenly, as if recalling something, Aizen turned around. "If only the Soul Society could stay like this forever."

Naruto was taken aback.

His sensory ability indicated that this statement was a "lie."

The day of the new term quickly arrived.

The presence of two captains at the event brought a broad smile to Dean Hakou's face.

Naruto, already accustomed to such occasions, recited the speech he had prepared the night before.

When he finished, Sōsuke Aizen took the stage.

His speech differed from the one Naruto had heard before; it seemed he rewrote it for each new batch of students every year.

At the end, Aizen smiled at them. "I hope you all become outstanding Shinigami."

"Every year, I release my Zanpakutō as a blessing for the new students."

"But this year, Captain Uzumaki is also here."

He turned and looked at the blonde figure in the audience. "Naruto, would you like to demonstrate for them?"

Naruto shook his head. His blade was not suitable for display.

Aizen raised his hand and placed it on his sword. "Then I'll do it as usual."

He drew his sword and began the incantation for its release.

"Shatter, Kyōka Suigetsu."

Illusions of flowing water emerged, reflecting false images.

The students gasped in amazement.

Naruto's gaze pierced through the illusory shadows before him, and he smiled as he fixed his eyes on Aizen at the podium. By now, such a level of "illusion" no longer affected him.

"Every Zanpakutō has different abilities," Aizen spoke softly. "This is mine."

After a moment, he sheathed his sword.

Dean Hakou scratched his head.

Something seemed missing this year.

After seeing off the two captains and making plans to meet Naruto later at a tavern, it suddenly struck him.

Captain Aizen had skipped the usual part when releasing his Zanpakutō.

In past years, when he demonstrated his "water-type" Zanpakutō to the new students, he always described its specific abilities—though not very powerful, it was one of the few in the Soul Society with "illusion" capabilities.

But this year, he hadn't explained.

Did he forget?

Or did he skip it because both captains' speeches ran long?

Naruto returned to the division quarters.

The lie that had slipped from Sōsuke Aizen's lips that day lingered in his mind.

But it seemed that was the only "lie."

Whether during the speech to the students of the Shin'ō Academy or in everyday interactions, Sōsuke Aizen remained the same sincere, gentle Captain Aizen.

Tōsen Kaname was also closely observed.

Although he maintained his usual demeanor, avoiding interaction with others during training and disappearing immediately after, Naruto had learned about Tōsen's "Shikai" from the members of the 9th Division.

It was called "Suzumushi," a Zanpakutō with hypnotic abilities.

"Hypnosis"—that was a power that intrigued him.

Though he had discovered its effects, he still couldn't figure out how it worked.

Did one fall under its spell by simply seeing it? Or was there another method?

As Naruto continued his research, he also kept an eye on them.

He had already made progress on the "Reaper Death Seal."

The results were almost identical to the conclusions he had derived from the scroll given to him by Orochimaru.

Indeed, it was a technique similar to "Summoning Jutsu."

Thanks to Orochimaru's work and the complete "Reaper Death Seal" technique, Naruto had even devised a way to undo it.

It required finding the "token" of the demon and using it to perform the ritual, summoning the Shinigami. When it appeared, one would cut open its belly, releasing the souls inside, allowing them to find their rightful place.

Fragmented souls would return to their bodies.

The dead would return to the Pure Land.

While Naruto's research was progressing smoothly, Kurotsuchi Mayuri was facing difficulties.

Finding a safe way to release the power from a Jinchūriki's body troubled him greatly.

Significant progress had been made recently.

Initially, it was impossible to ensure the survival of a rabbit after extracting the power, but now they could survive up to a week after the extraction.

But the significant toll this took on their lifespan was unacceptable to either Naruto or Mayuri.

Another year passed.

Naruto was handling matters in the division quarters.

"Captain." Vice-Captain Kotsubaki Jin'emon burst through the door in a hurry. "A Ryoka(旅禍, Traveling Evil(s)) has forcibly defeated the guards at the 'Blue Stream Gate' gate and broken into the Seireitei. He seems hostile and has already defeated several seated officers, though no fatalities have been reported yet."

Naruto stood up. "A Ryoka?"

"He's a man with long black hair, carrying a little pink-haired girl on his shoulder," Kotsubaki Jin'emon reported. "He's very strong."

"We haven't been able to gather more information."

"We couldn't even force him to release his Shikai."

~~~

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