The incident in Amegakure had finally come to a close—at least for now.
Nagato, still devastated by the deaths of his comrades and Yahiko's sacrifice, had no intention of joining Kirigakure, no matter how many offers of assistance Yoru extended—even promises to help him deal with Hanzō. He refused them all.
He wanted to destroy Hanzō with his own hands. He wanted to reshape this rain-drenched, broken country on his own terms.
No one can stop a young man who's willing to act on his ideals.
With nothing more to offer, Yoru gave him his blessing and returned to Kirigakure, bringing with him Uchiha Shisui—along with the bodies of over a dozen fallen Uchiha clan members.
"...So this is the Mangekyō technique Shisui awakened?"
Within the Bloodline Research Lab, Yoru sat quietly with his eyes closed, sensing the lingering energy in the Gigai's eye socket.
Shisui's left eye had indeed awakened the technique known as Kotoamatsukami, but it wasn't quite what Yoru had hoped.
This version of Kotoamatsukami could infiltrate a person's mind and alter their will undetected—subtly manipulating their thoughts without them ever realizing they'd been under genjutsu. Even after the effect ended, the victim wouldn't feel anything was amiss.
Clearly, this wasn't the same as Itachi's version of Kotoamatsukami, the one capable of permanently rewriting someone's will—but the one Danzō had once used to control Mifune.
Both had their advantages.
The permanent version could rewrite a target's mind entirely, but had a cooldown of more than a decade—essentially a one-time use.
The one Yoru had now, however, had a cooldown of only twenty-four hours, provided the user had enough chakra and ocular power.
"Still... I wonder if I reimplant a Three Tomoe Sharingan into him, could he reawaken the Mangekyō?"
Yoru muttered under his breath.
As for the Eternal Mangekyō in Shisui's right eye, it housed Amaterasu—the legendary black flames said to never extinguish until their target was reduced to ash.
Yoru was slightly disappointed, but not surprised.
That eye hadn't originally belonged to Shisui. It had come from his father—someone Yoru had never met, but from Shisui's description, he'd been a classic Uchiha: deeply conflicted between clan and village, ultimately seeking power to overthrow Konoha's leadership and place the Uchiha at the top.
And people like that—when they awakened the Mangekyō—almost always manifested Amaterasu as a reflection of their desire for overwhelming destruction.
"Lord Yoru," said Yukiko Fuyuna gently, "Do you intend to transplant one eye? Or both?"
"For now, let's just swap it with that Mangekyo..."
Yoru withdrew his spirit energy, returning to his original body, and pondered for a moment before speaking.
He had originally taken Shisui's eye for two reasons: to increase his resistance to genjutsu in the absence of Reiryoku, and to defend himself against the subtle, world-altering power of Kotoamatsukami. At the time, he had no means to resist such a technique.
Even though the Sharingan placed an enormous strain on his body, he still chose to implant it.
And honestly, even now, that hadn't changed.
Yes—outside of his Shikai and Bankai, Yoru's normal chakra reserves barely matched those of an average jonin. About one "Kakashi-level" unit, if he were to guess.
If he used Kamui two or three times, he'd be on the verge of collapse. Sure, once he activated Shikai or Bankai, he could last longer—but the Mangekyō's internal ocular power might not hold up.
And that was with just one eye.
Two would double the drain.
"This body… it's already pushed to its limit."
As Yukiko carefully replaced his right eye, Yoru couldn't help but sigh inwardly.
He hadn't been cast out by the Yuki Clan without reason. He had failed to awaken Ice Release, and his natural potential—even at best—was ordinary at best.
Without the System, and the abilities he'd gained through point-based enhancements, there was no way he'd have become the Fourth Mizukage. Hell, he would've died long ago to some random AoE on the battlefield.
No—he wouldn't have even made it that far. He would've died in Kirigakure's infamous Blood Mist Graduation Exam back when the Third Mizukage ruled.
"It's done, Lord Yoru."
Before long, Yukiko finished replacing Yoru's eye. She then carefully removed Shisui's three-tomoe eye and the Eternal Mangekyo from the gigai's eye and sealed them away in a container.
Yoru slowly opened his new right eye.
The four-pointed shuriken pattern of Shisui's Mangekyō spun, glowing with an eerie, unsettling light.
He activated it—and immediately winced.
No clarity. No revelation.
Just a wave of dizziness and stabbing pain at the back of his skull, followed by the Sharingan's usual enhancements and jutsu data.
"It was exactly the same as when it was in the gigai!"
Unlike when he'd implanted a Three Tomoe Sharingan and felt the world sharpen, the Mangekyō's activation triggered a nerve-shocking backlash.
He deactivated it. The Mangekyō retreated to a three-tomoe form, and the dizziness faded.
"Neurological links are stable. Chakra and ocular energy flow is fine... so it must be rejection."
Yoru understood instantly.
The Sharingan's strength was known across the shinobi world—but so were the dangers of transplanting it into non-Uchiha bodies.
Unlike the Byakugan, which drained chakra but had manageable side effects, the Sharingan was built for combat. It demanded constant chakra support—and punished those who couldn't handle it.
Even someone like Kakashi, who awakened the Mangekyō in a Sharingan gifted by Obito, had needed over a decade of trial, error, and chakra refinement to properly use it.
"What a pain…"
Yoru sighed deeply and replaced his eye-covering mask.
The world of Naruto had always been built on one absolute rule:
Bloodline is destiny.
Those born with Ōtsutsuki lineage were placed at the top of the world from the moment they took their first breath.
The Senju. The Uchiha. The Hyūga. The Uzumaki. The Kaguya.
All inheritors of divine bloodlines, destined to be the main characters of the shinobi world.
Then came the ordinary kekkei genkai clans like Yuki and Kurama, serving as supporting characters.
And at the very bottom were the "Secret Technique" clans—like Nara, Akimichi, Sarutobi, and Momochi. Their jutsu were cool, sure… but they were nothing more than narrative filler. Background noise.
Then there were people like Yoru—a half-blood with no awakened kekkei genkai, no natural gifts, and no place.
"What a brutal and unforgiving world…"
Under Yukiko's bewildered gaze, Yoru chuckled self-deprecatingly.
Without the System, he would have been born at the very bottom of the pyramid. Even with Gensui's kind adoption, his only role in the future, besides highlighting those glamorous characters, would have been to become a mere White Zetsu in years to come.
"Is something wrong, Lord Yoru?"
"No. Nothing."
Yoru shook his head, casting aside his pointless lamentations. He looked at Yukiko, whose eyes were red from her research: "How's your research coming along?"
"I've been cross-testing your genetic samples with various kekkei genkai lineages in the village, as well as with Hiromi's Uzumaki DNA. There were some... curious results."
"The Kaguya Clan's samples were the most aggressive. Extremely unstable fusions, high rejection rates—even when cell compatibility was achieved, nearly 80% of the results mutated uncontrollably."
"The most stable? Uzumaki cells. Your DNA fused almost perfectly with Hiromi's—virtually no rejection. But strangely, the Uzumaki cells' regenerative properties were weakened post-fusion. It was like… transmutation in reverse. Turning miracle into rot."
"More strangely, this effect happened across nearly every donor—not just yours."
"Then I tried combining Kaguya and Uzumaki cells directly. After many failures, I found that under very specific conditions, they began to merge as if they were originally from the same source. Almost like… brothers."
Yoru raised an eyebrow.
She's not wrong.
The Kaguya weren't native to the Land of Water. They'd migrated from the Land of Fire for unknown reasons.
Add to that their occasional ties to the Hyūga and their distinctly Ōtsutsuki-like appearance…
It wasn't hard to imagine a shared ancestry with the Uzumaki—descendants of the Senju, themselves descended from the Sage of Six Paths.
As he recalled some highly classified dossiers from the Mizukage Archives, Yoru withdrew a scroll from his tool pouch.
With a puff of chakra smoke, a small amount of pure white substance appeared on the lab table.
"What is this…?"
"A special cellular sample. One of the things I picked up along with those Sharingan."
Yoru handed it to Yukiko. "Try fusing it with mine. With the Kaguya. With the Uzumaki. Even the Uchiha. See what happens."
Intrigued, she took it and placed a sample under her microscope.
Almost immediately, her expression changed.
"This is incredible. The cellular activity is ten times higher than any normal human tissue. Even compared to Uzumaki or Kaguya samples—this is on another level!"
"But there's more… despite its vitality, it doesn't seem aggressive at all. Let me analyze it further…"
Yoru gave a faint smirk.
As expected.
Those white cells were no ordinary tissue—they were White Zetsu Cells, harvested directly from Shisui's body.
This isn't just any White Zetsu from under the God Tree; it's a special artificial human created by Uchiha Madara using the God Tree and Hashirama's cells.
This type of White Zetsu contained quite a bit of Hashirama's cells, making it extremely valuable for research and transplantation. Its limbs could even be used as immediate plug-and-play organs, just like the Sharingan, practically a mobile organ bank, a blessing for countless disabled individuals!
If they could isolate the right traits, it would revolutionize Kirigakure's medical tech and weaponize every lab-grown shinobi project they had.
Yes.
To elevate Kirigakure's overall strength and to transform his own mediocre physical body, besides the 'Shinigami Project' led by Uzumaki Hiromi, Yoru had also formulated numerous forbidden plans that couldn't be made public.
Plans he couldn't share publicly.
Projects like:
Analysis and Replication of Ninjutsu-based Kekkei Genka
Feasibility of Organ-based Kekkei Genkai Transplants
Certainty of Kekkei Genkai Offspring Birth
Kekkei Genkai Bloodline Fusion
Among these forbidden plans, some were already being researched by Kirigakure, like Ao's Byakugan, which was a significant result of organ-based kekkei genkai transplantation.
As for the others, such as 'Analysis and Replication of Ninjutsu-based Kekkei Genkai,' these plans initially began due to certain discoveries.
One was the Third Tsuchikage, Ōnoki of Both Scales.
Despite having no blood relation to the Second Tsuchikage, he somehow mastered Dust Release, a kekkei tōta that surpassed kekkei genkai. This astonished the entire shinobi world.
The second was the Land of Snow.
A country full of people using Ice Release without any Yuki Clan bloodline at all.
That intel had nearly sparked war between the Yuki Clan and the Snow Country—until it was discovered that while their techniques were similar, the power gap was massive. And Snow's lack of resources made any invasion a waste of effort.
Still, it proved a terrifying truth:
Kekkei genkai could be learned. Or recreated.
The Third Mizukage was too corrupt to act on that.
But now that Yoru was in power…
It was back on the table—alongside every other forbidden research initiative.
"The poor rely on mutation; the rich rely on technology."
"As the Fourth Mizukage, I will achieve my transformation through technology!"
Gazing at the room filled with bottles and jars, various organs, and grotesque sights, Yoru took a deep breath.
Soul experiments, the complete creation of Shinigami forms—he wanted it!
Various research into the Naruto world's physical kekkei genkai—he wanted that too!
He was going to tackle this with both hands, making both Bleach and Naruto powers blossom!
PS: Read Advance Chapters at https://www.patreon.com/c/ReadJin