Constructing a Concentrated Spirit Zone demands an immense number of souls. If preparations had been made in Kirigakure decades ago, the village, as the Bloody Mist, would certainly have become a Concentrated Spirit Zone.
The Third Mizukage's Bloody Mist Policy ensured that the number of lives lost annually in Kirigakure was comparable to a small war. Especially the ninja academy's graduation exam, where students were forced to kill each other, claimed countless young lives.
Yet all those souls have drifted into the Pure Land. And under Yoru's rule, he can't simply butcher villagers to rebuild the soul reservoir.
The only option now: harvest souls from outside.
Over the past three months, Yoru executed death-row prisoners and performed Edo Tensei on regular shinobi—collecting some souls, though far too few for a Concentrated Spirit Zone.
There's only one place he can gather the quantities he needs, discreetly: the battlefields of the war between Land of Fire and Earth.
Originally, rashly intervening in the war between the Land of Fire and Earth would inevitably draw criticism. But now, the Third Hokage's letter provided him with the perfect justification!
Kirigakure and Konoha were now allies with a shared purpose; their presence on the battlefield was entirely reasonable!
"However, directly collecting flesh and blood, or using special sealing methods to gather souls, would inevitably attract the attention of observant individuals. If only I had the Rinnegan, it would be so much more convenient..."
Yoru murmured. The abilities of the Rinnegan's Human Path and Naraka Path were simply the bane of souls.
Just standing on the battlefield, a single pull from the Rinnegan would gather all the souls that ordinary people couldn't even perceive.
But alas, Nagato had no intention of cooperating with him, nor could he entrust this mission, crucial to the future development of his Shinigami Plan, to Nagato, whose mind was now warped.
"Mizukage-sama!"
Suddenly, a bright figure knocked on the Mizukage's office door. Fuyuna Yukiko, her red eyes shining, could barely contain her excitement.
However, upon seeing Yuki Akira in the office, her expression momentarily froze.
"It's fine. Speak."
Yoru waved his hand. Only then did Yukiko excitedly announce, "We've achieved significant research results regarding the Hashirama's Cells and the Mangekyo Sharingan you provided!"
"Is that so!"
Yoru's expression sharpened. "Elaborate!"
Three months ago, Yoru used Kotoamatsukami to control Danzō. Besides obtaining a vast quantity of Forbidden Jutsu scrolls, secret techniques, and various forbidden research data, including Wood Release and soul experimentation data, he also took a small portion of the Hashirama's Cells from Danzō's body.
Danzō had been severely wounded by Yoru's Hyōrinmaru. Although he narrowly escaped death using Izanagi, the subsequent damage still caused him immense trouble.
To maintain his condition, Danzō immediately underwent surgery using Hashirama's Cells upon returning to Konoha. It was precisely because of this that Yoru acquired the Hashirama's Cells from him!
"Hashirama's cells are incredibly active. Even without nutrients, they remain stable and energetic outside the body. But they're also extremely aggressive — their chakra tends to manifest physically. If the energy balance isn't carefully controlled, they'll trigger uncontrolled Wood Transformation."
"However, by using White Zetsu cells as a nutrient base, we managed to stabilize the growth of Hashirama's cells and successfully complete the initial development phase."
Yukiko could barely contain her excitement. "In addition, using the data and ideas you provided, we attempted to combine your gigai with the Hashirama's Cells. After multiple studies, we successfully developed a 'fusion agent' that, to a certain extent, stabilizes the Hashirama's Cells. It's made from Yumi's Uzumaki Cells combined with White Zetsu Cells, with a touch of Kaguya Clan Cells added."
"And more importantly, after injecting your gigai with Uchiha cells and then implanting Hashirama's cells, we observed something unexpected—your Mangekyō Sharingan, which had suffered severe degeneration, actually began to regenerate its dōjutsu power."
Fuyuna Yukiko excitedly recounted the latest research findings. The terminology used left Yuki Akira, who only knew a few details, utterly dumbfounded.
Uzumaki Cells, Uchiha Cells, Mangekyo Sharingan, Hashirama's Cells...
Uzumaki cells, Uchiha cells, the Mangekyō Sharingan, Hashirama's cells…
There was no mistaking it—when discussed alongside such elite bloodlines, the term clearly referred to Hashirama Senju. No one would confuse it with the First Mizukage, Byakuren.
In just a few short months since taking office, had Yoru really pushed Kirigakure's Kekkei Genkai research this far, all without anyone noticing?!
Kirigakure's foundational capabilities alone naturally couldn't achieve this. . It was entirely thanks to the resources obtained from Danzō.
The materials he provided—scrolls, data, and forbidden research—allowed their work to build directly on the foundation laid by both Danzō and Orochimaru. Combined with the full backing of a Kage-level figure like Yoru, this kind of rapid progress became possible.
"Excellent work, Yukiko!"
Yoru nodded approvingly. The cultivation of Hashirama's Cells and the recovery of his Kotoamatsukami Mangekyo Sharingan's dōjutsu power were undoubtedly delightful surprises, explaining Yukiko's excitement.
Right.
Since Hashirama's Cells could now be mass-produced and even implanted into human bodies, didn't that mean...
"Akira, how's Uchiha Shisui doing?"
"Uh, not so good."
Yuki Akira composed herself and spoke quietly. "Natural reproduction is far too slow, and that Uchiha's physical condition isn't ideal. It simply can't meet the demand of the hundreds of people in our village who are waiting."
"Due to these limitations, we've recently relied on direct extraction methods to collect viable samples. The next step is to proceed with artificial insemination for controlled reproduction."
"Using these methods, the village has successfully inseminated over a hundred women, and a large supply of viable samples remains cryogenically stored for future use."
"As for Uchiha Shisui... it's certain he's not dead yet."
"..."
Yoru silently mourned for Shisui's 'kidneys' for a second. He could have at least enjoyed himself before, but now it was direct, forceful extraction.
Just imagining the scene, Yoru couldn't help but feel a pang in his own 'kidneys,' empathizing with the sensation...
"Now that we have more than enough Uchiha samples, it's time our Uchiha prodigy was put to better use."
"You mean..."
"Yes. It's time to create something extraordinary."
Uchiha Shisui's eyes were numb as he stared at the familiar ceiling. Like a machine, he slowly rose from the bed and began to wash up.
Three months had completely transformed this prodigy of the Uchiha Clan into Kirigakure's 'producer.'
Despite receiving abundant nutrition daily, his body had grown increasingly thin, even more so than Nagato's after being drained by the Demonic Statue of the Outer Path.
His eyes were deeply sunken, his cheeks hollow, heavy dark circles under his eyes, and pale lips, coupled with legs that trembled even when he walked.
Everything indicated that this young boy's body had reached some sort of limit.
The luxurious meals tasted like cardboard to Shisui. After eating, he drank two more nutritional supplements, then walked towards the door, speaking to the female Anbu stationed there.
"Let's go."
"Don't be in such a hurry. You have a different mission today."
"What—what?!"
The female Anbu's voice made Shisui's steps halt.
The nearly dried-out young man abruptly turned to face the female Anbu. His dull, listless eyes suddenly seemed to ignite with light!
"What kind of mission is it... I don't care, as long as it's not that, anything will do!"
"Heh, I hope you can still wear that expression later."
The female Anbu smiled faintly and quickly led Shisui into a gloomy corridor.
The dark environment carried a hint of chill, and Shisui's mind couldn't help but conjure a few guesses.
When he reached the end of the corridor and saw the ninja standing at the doorway, his pupils suddenly contracted.
"You—you're!"
"The Uchiha Clan's prodigy, huh? I hear you've made significant contributions to the village these past few months."
Kurushirare Kushimaru stood with his arms crossed, opening the door behind him. "I hope you can endure it. The Mizukage-sama has placed high hopes on you."
Forbidden experiments, then!
Gazing at the person who should have been dead, yet stood alive before him, Shisui's heart already knew what awaited him.
It made sense. He had been utterly exploited for three full months. Even with daily nutrition and medical ninja present, he had reached his limit.
Perhaps because his efficiency was too low to meet demand, Kirigakure had abandoned natural methods altogether. In the past few weeks, the ANBU began extracting samples directly, harvesting large quantities for artificial insemination.
Now, all of Kirigakure had no shortage of Uchiha 'samples.' His only remaining value was probably for those forbidden experiments.
The light in Shisui's eyes gradually faded, but a sense of relief flickered within them.
Dying like this might not be so bad after all...
"You better hold out, Shisui-kun."
Yuki Yoru, clad in his Fourth Mizukage's Kage Robe, watched Shisui walk in with a smiling expression. "If the experiment fails, to mourn you, I might just turn your 'performances' from this period into a film and send it to a distribution company, ensuring all your efforts become an artistic masterpiece passed down through the ages."
"Wh—what?! No! Absolutely not!"
Shisui, who had just been contemplating relief through death, immediately envisioned a scene far more terrifying than any nightmare upon hearing Yuki Yoru's words, and he felt a shiver run down his spine.
"I will definitely persevere! Whatever you do, I will cooperate with you! Please don't do something like that!"
"That depends on your performance, then."
"If you truly perform exceptionally well, not only will I not release your artistic 'performances,' but I will also entrust you with a vital role, allowing you to flourish anew in Kirigakure."
"What do you say? How does the position of clan head of the Kirigakure Uchiha sound?"
Yoru displayed a gentle smile, and a spark of chakra appeared on his fingertip, striking Shisui's lower abdomen.
"Four Symbols Seal: Release!"
"Ugh!"
Shisui's body suddenly arched, but immediately afterward, the chakra that had been sealed within him for over three months surged forth again, finally bringing a new vitality to his weak and depleted body.
The return of his power did not bring a look of joy to Shisui's face. He knew full well that Yuki Yoru unsealing his chakra meant that what he was about to face would be terrifyingly difficult!
But...
"Bring it on!"
Shisui's tone was resolute, his expression one of complete resignation.
"Don't be in a hurry. Before that, I hope you can hand over your father's other eye, to facilitate our upcoming experiment."
"What... I understand."
Shisui bit his lip lightly, formed hand seals, and slammed his hands onto the ground. "Summoning Jutsu!"
The next moment, a ninja cat with pointy ears and disheveled, raccoon-like fur appeared before them.
"This chakra... Shisui? Weren't you already..."
"Don't talk, Denka. Give me that eye," Shisui interrupted the ninja cat named Denka, speaking hastily.
The ninja cat paused slightly, then finally noticed its surroundings. A look of terror instantly appeared on its feline face. "I—I understand, meow. Please don't harm me or Shisui-kun, you people of Kirigakure, meow!"
Its furry paw rummaged around its body, and a glass jar containing a Three-Tomoe Sharingan was produced from seemingly nowhere.
"Here, meow."
"Thank you, Denka. You can go back now."
"Don't be in a hurry. One must do things cleanly, mustn't one?"
Shisui patted the ninja cat named Denka. Just as the ninja cat was about to leave, it was stopped by Yoru.
The ninja cat recoiled in fright, instinctively looking at Yuki Yoru. But what met its gaze was a spinning, four-bladed pinwheel!
"Genjutsu! Sharingan!"
Memory Wipe!
"All right, Shisui. You can cancel the Summoning Jutsu now."
"Yes."
Gazing at the perfectly flawless Yuki Yoru, Shisui helplessly canceled the Summoning Jutsu, sending the memory-wiped Denka back. At the same time, he handed the Three-Tomoe Sharingan to Yuki Yoru.
"The eye you wanted."
"No, this is your eye."
Yoru shook his head. "I don't know if it's due to emotion, or some other triviality, that made you unwilling to accept your father's left eye and evolve both eyes into the Eternal Mangekyo Sharingan. But now, I need you to implant this eye, and at the same time, I will return your original Eternal Mangekyo Sharingan to you."
"This is the foundation for what we're going to do next, so please lie down on the operating table first."
"...Yes."
Shisui opened his mouth, wanting to say something, but ultimately complied and lay down on the operating table, allowing FuyunaYukiko, who was already prepared, to remove the ordinary eyes from his eye sockets. Then, she simultaneously implanted this Three-Tomoe Sharingan, belonging to Uchiha Kofū, and his own Eternal Mangekyo Sharingan (which had integrated his father's power).
Feeling the long-lost power of the Sharingan, Shisui's heart, however, couldn't find any joy...