Mayuri Kurotsuchi demonstrated the results of his recent work.
He summoned a rabbit and tossed it to Retsu Unohana.
"This is what happens when the sealed power is released from the rabbit," he said coldly, even cruelly. "Now that Lieutenant Kuchiki is in this condition, using a rabbit as a test subject seems inappropriate."
"In my opinion…"
He turned his head to Naruto. "Let's experiment on a soul instead."
"How could such a weak and powerless creature compare to a human?"
The people in the room reacted differently.
Unohana's expression didn't change.
Byakuya Kuchiki frowned slightly.
Shunsui Kyōraku and Naruto both gave sharp looks.
"If you dare do that, I'll cut you down," Naruto narrowed his eyes. "Captain Kurotsuchi, don't say things that could be dangerous for you."
Mayuri clicked his tongue, turned his head away, and avoided looking at Naruto again.
He knew this suggestion would be rejected—he just couldn't help but say it aloud.
"Thank you for your concern, Captain Kurotsuchi," Soujun Kuchiki said gently. "But I'm not so precious that others need to sacrifice themselves for me. Besides, it doesn't affect my life."
Mayuri seemed to recall something. "What about Tōsen's corpse?"
"Captain Uzumaki, bring it out. He's already dead and a criminal. Using his corpse should be fine, right?"
Naruto reached out and summoned a scroll.
He had no psychological barrier.
Using a dead person's body to heal the living was nothing difficult to accept.
Mayuri's eyes gleamed with greed as he extended his hand.
But Naruto swung the scroll past him and handed it to Retsu Unohana.
"For me?" Unohana looked surprised.
Mayuri protested dramatically, "Ah, ah! Captain Uzumaki, I'm the researcher here!"
"Such a valuable thing, and you won't let me study it?"
"Do you not trust me?"
Naruto looked at him coldly. "If we were on the battlefield, I'd gladly entrust my back to you."
"But in research? If not restrained, you're someone who completely lacks self-control."
Mayuri was a madman.
His passion and drive for research surpassed any scientist Naruto had ever seen. But it also meant he had no limits—he'd do anything to achieve his goals.
Over nearly the past two years, he had constantly tested Naruto.
After each warning, he'd restrain himself for a bit, but soon enough, his true nature would resurface.
The only difference was whether it was in the open or in secret.
If it weren't for Naruto being stronger, and Captain-Commander Yamamoto keeping him in check, Mayuri might have tried kidnapping Naruto already.
Naruto then turned to Unohana with a gentle tone, "Captain Unohana, I'm entrusting Tōsen's corpse to you."
"If Captain Kurotsuchi wants to study it, please accommodate him when you have time."
Unohana glanced at Mayuri and smiled faintly. "Naruto, you really trust me."
"Don't worry. Captain Kurotsuchi will behave."
Mayuri wanted to speak, but sensing the sharp intent behind Unohana's gentle tone, he turned his head away.
Forget it.
He'd go along with this—for now.
Though he was under someone's control, getting Naruto's permission to study Tōsen's body was already a major breakthrough in research.
They got to work.
Disassembling the Four Symbols Seal and analyzing the life structure of a Jinchūriki.
Naruto assisted.
By evening, Naruto invited them for drinks. As for the Kuchiki clan, Byakuya took the lead. With Soujun being forced to retire early, his grandson would now bypass his father and succeed his grandfather as the clan's head.
Ginrei Kuchiki was already very old. He could continue as a captain for a few decades longer, but he was just waiting for Byakuya to fully master Bankai before retiring.
Mayuri didn't attend.
He disliked drinking with Naruto.
That blond brat always inspected his cup before each sip. And if he drank too much, he'd beat Mayuri up.
Sure, Mayuri was indeed always thinking of ways to steal Naruto's body data—but couldn't the guy show a little more trust?
At the izakaya…
After a few drinks, Shunsui Kyōraku slapped Byakuya on the shoulder. "Even though you'll be vice-captain soon, don't always keep that stiff face and carry everything alone."
"I'm the heir of the Kuchiki clan," Byakuya said firmly, shaking his head. "I must set a proper example."
He couldn't fall short of his father.
And he certainly couldn't end up like the disgrace of the Tsunayashiro clan.
Kyōraku sighed.
He could easily advise Naruto, but when it came to Byakuya, it wasn't his place to say too much.
He turned instead. "Naruto, I heard your Bankai training isn't going well?"
Unohana also looked over.
"It's true, not going smoothly," Naruto nodded calmly. "There are some issues."
"Want my help?" Kyōraku offered.
Naruto looked surprised. "Uncle Shunsui, aren't you the one who hates trouble the most?"
Kyōraku set his cup down in annoyance. "If a cute junior is dealing with something they can't solve alone, I'm more than happy to lend a hand, okay?"
"Even if I'm a guy," Naruto chuckled.
Kyōraku sighed and waved to the owner, ordering two more bottles of good sake. Just for that line, he was ready to drink all night.
Unohana added kindly, "Naruto-kun's progress is indeed a bit unusual."
With his talent, there should've been some signs of manifestation by now.
Even if…
The blade known as "Kurama" wasn't entirely his own internal power.
Naruto shook his head. "Thank you both for your concern."
"But this is something I have to resolve on my own. I just need a little more time."
Kyōraku relaxed. "As long as you're confident."
He was a bit worried—perhaps something had changed in Naruto's body again.
But Naruto wasn't the type to bear things alone without asking for help. Since Kyōraku had asked directly and Naruto hadn't mentioned needing support, it probably wasn't anything too serious.
With that, he stood up and called over Rangiku Matsumoto and Isshin Shiba.
If there was no trouble—then time to drink and relax.
Aizen Sōsuke was extremely cautious. After meeting Naruto, he hadn't slipped up once.
His behavior remained unchanged—still the same gentle Fifth Division captain.
He seemed to have backed off.
In the ten years since that day, no Soul Reapers or Rukongai residents had mysteriously disappeared.
It seemed the warning had worked.
But Naruto… felt like Aizen was still plotting something.
That guy had the deepest, most brilliant light in his eyes out of everyone Naruto had met.
There was no way he'd back down because of one warning.
Naruto kept an eye on him, but it didn't interfere with his own life.
As for the "Hollow" sealed within Soujun Kuchiki, it still couldn't be extracted—not because the release formula hadn't been developed.
Unohana and Mayuri confirmed that the Four Symbols Seal fused both life forces together.
To separate them required many factors.
Time since sealing was one—newer seals were easier to undo because the forces hadn't completely merged.
The relative strength of the sealed force also mattered.
If it was stronger than the host, separation would be harder. If weaker, it would be easier.
Rabbits weren't good test subjects.
Switching to larger animals—wild boars, black bears—yielded results more quickly.
The "Hollow" inside Soujun wasn't especially strong—on par with him, about a lieutenant level.
But the problem was…
He was physically frail. If separation was attempted, it would cause irreversible damage to his life force.
Kuchiki clan honor was important.
But so was a person's life.
Ginrei Kuchiki made the final call—not to force the separation of the Hollow inside Soujun.
The research goal shifted to how to coexist with the Hollow's power.
Which was exactly what Naruto needed.
Kurama had been sealed inside him for over forty years. Their life forces were fully merged, making separation nearly impossible.
Fully breaking the seal without harming either of them was no longer a viable option.
Even if it were possible, who knew how long it would take.
So before that, finding a way to temporarily release Kurama was critical.
Mayuri, being the madman he was, thought:
If you can't separate it, why not convert Hollow power back into Shinigami power?
In the past ten years, he developed a formula that could temporarily extract the internal power without harming the host's life force.
Of course, his real goal was to extract and modify the Hollow power.
But the technique helped Naruto a lot.
In Naruto's inner world—
Kurama looked at the written formula and nodded thoughtfully. "I don't understand this stuff, but that guy really is something."
"To achieve this kind of result…"
Naruto sat cross-legged and smiled. "Once we return to the ninja world, we can test what this technique is really capable of."
"Don't worry, ten years will pass quickly."
Kurama bared his teeth. "That Aizen guy is just too damn annoying."
Even as a pure energy being, with a near-infinite lifespan…
Ten years wasn't too much to wait.
But still…
That guy was just too detestable.
Naruto was about to speak when his senses suddenly reacted.
He exited his inner world and opened his eyes.
Captain Jūshirō Ukitake, led by Kotsubaki Sentarō, pushed open the door, looking anxious.
(End of Chapter)