A Zanpakutō is, fundamentally, a weapon forged from a Shinigami's own soul. A Shinigami must learn their Zanpakutō's name, commune with it mentally, and then perform a Shikai to release its power—that's the essence of Zanpakutō release.
When Yoru transformed souls into Shinigami, he implanted an Asauchi in each of them. One purpose was to help them adapt to Shinigami power; the other was to allow them, through naming and bonding their Asauchi, to awaken their own personal Zanpakutō. He wasn't planning to do it all himself.
Soul experiments? Done by him. Asauchi? Provided by him. Naming the Zanpakutō? That he left to them—because everything costs points. Yoru wasn't an accountant, but he was saving points to exchange for the Hōgyoku and Schrift, so nothing could be wasted.
Of course, Yoru was curious to see what types of Zanpakutō his new Shinigami would awaken—though he himself could not.
He'd asked the system why he couldn't awaken a Zanpakutō, and the system replied:
"You are the source of all Shinigami power in this world—an amalgam of Hollow, Shinigami, Quincy, and human. Your power is this system."
Yoru dismissed it as empty fluff—just another way for the system to siphon his points.
He made it clear:
"Releasing a Zanpakutō is ultimately an expression of your inner power—your self fused with your soul energy. To release it, you must understand your own heart and why you exist. Only then will its power manifest."
Kuriarare Kushimaru, ever blunt, thought, "We're former Bloody Mist goons—brains wired for killing, grabbing power, money, women. We don't do soul-searching." He prodded Yagura with a shove.
"Explain this to me later, okay?"
Yagura shook his head firmly:
"Mizukage-sama's right. This power must be awakened through personal insight—you can't force it."
Kuriarare sighed—We've been colleagues before death, now we're revived as Shinigami, and you're still keeping secrets from me!
Uchiha Shisui, freshly out of his experiment, was puzzled. He'd seen Kuriarare revived—his own resurrection was due to forbidden experiments—but Zanpakutō and Shinigami talk? He didn't understand, though a few terms piqued his curiosity.
He asked quietly, shoulder aching from the implanted Sharingan:
"Are you conducting soul experiments? These people—dead—and yet revived... Mizukage Yoru, are you playing with souls?"
Yoru looked at him calmly and motioned to Yukiko to implant a Three-Tomoe Sharingan into Shisui's shoulder.
"No, you've misunderstood. I'm giving these Mist warriors a second chance at life. Bringing them back from the darkness of the Pure Land so they can return to their homes, right unfinished business, and continue the lives that were cut short."
"So don't accuse me like some outsider. I am not like your Konoha's evil Second Hokage, Senju Tobirama—who toyed with souls and created the forbidden Impure World Reincarnation!"
Shisui's face went pale—Tobirama created that jutsu?
The pain in his arm deepened as he realized the three-tomoe Sharingan was unnaturally embedded there.
"Impossible! Even if Tobirama created such a jutsu, surely it was for the village's protection!"
Yoru sneered:
"I could list Konoha's shady deeds all day. We have confirmed intel that would collapse Konoha's leadership from its pedestal into the mire. White Fang's suicide, infant experiments, Uchiha subjugation policies..."
He pressed on:
"I don't have time for storytelling now. In three days you'll take part in the next experiment. Meanwhile, I can send you the documents—for you to truly confront what your village's leaders have done and have your worldview shattered."
Then he asked quietly:
"One more thing—you know how to use Izanagi, right?"
"...Yes."
Yoru nodded:
"Good. Rest well. I'll have the Anbu deliver those documents. Yagura, tell us about your Zanpakutō release—the state of mind, the changes…"
Yagura paused, then carefully shared his experience, as Kuriarare squeezed in beside him to listen. Meanwhile, Shisui was escorted home by Anbu.
Despite wielding one of the most terrifying eyes in the shinobi world—fused with Hashirama's cells and a perfected Uchiha legacy—Shisui didn't try to run. He quietly waited in his residence. Soon, the Anbu arrived bearing the promised files:
"These are high-level intelligence records from past Mizukage—strictly classified. It's unexpected you, as a... breeding instrument, would be allowed to see them."
Shisui snapped:
"Shut up."
His blood-red Sharingan caused her to pause as she set down the files and withdrew.
The first document made him freeze:
"Second Hokage's Surveillance & Isolation Measures Against the Uchiha Clan"
Reading on, he recoiled:
Tobirama had established a secret Uchiha Police Force to "punish criminals," purposefully marginalizing the Uchiha people and keeping them outside Konoha's political circles. The plan was to incite Uchiha unrest to weaken Konoha—though, shockingly, the clan had accepted it, even welcomed it.
Shisui's eyes narrowed as he opened the next file—detailing Danzō and Orochimaru experimenting on infants to study Wood Release and the Sharingan.
Danzō? Not surprising—he was Konoha's dark underbelly. But Orochimaru?
He had been Hiruzen's student, even a candidate for Fourth Hokage. Yet he conducted infant experiments? That was darker than even Yoru himself!
Shisui trembled—it was confirmed that Konoha had successfully produced at least one Wood Release user via these experiments, presumably the escaped one rumored months ago.
He set that file down and turned the next, only to find documentation proving Konoha's elders had driven White Fang to suicide.
Three days later, Yoru visited Shisui again.
"You don't look well, Shisui-kun. You looked better during the breeding sessions. Want to jump back in? With your strength, now enhanced by Hashirama's cells, you could beat your hundred-a-month record."
Shisui's Eternal Mangekyō showed no emotion.
He thought of how he had sacrificed his own father for the village, only now to discover everything he believed was corrupt.
Faith broken.
"Let's begin the experiment then," he said faintly. "What's the plan?"
Yoru frowned:
"That dead look won't help. I intend to make you experience the edge of life and death, so you can grasp why it's so powerful—so the Power of All Creation you hold can evolve."
"But now you look like a corpse. If I stab you next, will you succumb, give up Izanagi, and just die?"
Shisui remained expressionless.
Yoru sighed:
"My dear Shisui-kun, everyone knows Konoha's darkness—only you who grew up under the so-called Will of Fire haven't seen it."
"'Where tree leaves dance, the flame lives on...' That's for the favored—the powerful, the landowners, the ruling clan. The Will of Fire is just propaganda used to control and manipulate you."
Shisui's Eternal Mangekyō flared—his chakra and dōjutsu shook the lab. His crimson eyes burned like a man-eating lion—but in the end, nothing changed. Only a young man shattered.
Yoru shook his head:
"You shouldn't look like that. Understand this, Shisui—you mean nothing to Konoha. Have things changed because you were gone?"
"No."
Yoru continued:
"Konoha remains the same. You valued it, but it doesn't value you. So why not focus on someone who does?"
"Kirigakure favored you—you've sired hundreds of children there. Once they're born, I'll name you head of the Kirigakure Uchiha. I'll fund them all monthly."
"Enough!" Shisui interrupted, visibly embarrassed.
Yoru grinned:
"Alright, alright. The experiment begins now—remember to use Izanagi."
Then he plunged Hyōrinmaru into Shisui's chest.
Agony surged through Shisui—he spat blood and slumped against Yoru.
"Relax... breathe deep. Feel the power—then use Izanagi."
Shisui trembled, life force draining. A few breaths later, he was gone—yet moments later, he reappeared, untouched.
His Eternal Mangekyō had transformed: faint purple ripples—constellations swirling in his irises.
Yoru's joy exploded:
"Hahaha—It worked! It worked!"