"What's going on here?"
Naruto asked, bewildered.
The man who had been as massive as a bear just moments ago, Shinnō, had suddenly shriveled into this frail, withered old man.
"Cells," Kiyosuke replied.
"Cells?"
"So that's it," Sakura said, realization dawning on her. As Tsunade-sama's disciple, it didn't take her long to piece together the truth.
Sasuke thought it through and quickly caught on as well. Only Naruto was left scratching his head, completely lost.
"So, Sakura, what's actually going on?"
"Honestly, Naruto, you're hopeless. Even after training with Jiraiya-sensei, you never bothered to learn basic knowledge?" Sakura sighed helplessly. Dealing with Naruto's cluelessness was an endless struggle.
She began to explain, "Human cells have a limit to how many times they can divide. Normally, they can only split fifty to sixty times. After that, the cells stop renewing themselves, and the corresponding tissue begins to age. Medical ninjutsu uses chakra to stimulate cells at the site of an injury, speeding up division and recovery, but in theory, that process still eats away at the patient's lifespan. It's just usually not enough to matter."
She paused, then continued, "Shinnō's medical ninjutsu works by reactivating and revitalizing the body, forcing recovery through chakra stimulation. But once the cells hit their limit, the body inevitably ages. Kiyosuke-sensei's attacks kept wounding him, pushing his cells to divide at an accelerated pace. The faster the division, the faster the aging—this is the result you see now."
Human cells could only divide fifty to sixty times. Only the infamous cancer cells were able to proliferate without limit, endlessly spreading and destroying healthy tissue.
Even if Shinnō possessed the power of the Zero-Tails—able to regenerate and stimulate cell activity—he couldn't surpass that limit. At best, the Zero-Tails could raise the cap, but under relentless damage, the number would eventually be reached. And once it was, aging was inevitable.
"You… you calculated this from the start?" Shinnō wheezed. His murky old eyes glared daggers at Kiyosuke.
"More or less," Kiyosuke said casually. "The human body has its limits. But honestly? I mostly just wanted to see this look on your face—that bitterness, that unwillingness, that desperate urge to kill me. Hahahahaha!"
"Onore… Asakawa Kiyosuke!" Shinnō cursed.
"Your strength is pathetic," Kiyosuke sneered. "I don't even need any flashy techniques. Pure taijutsu is enough to beat you into the ground. You're a disappointment!"
He ground his foot into Shinnō's face and ordered,
"Hurry up and hand over your jutsu. I want to see what kind of technique Orochimaru has been obsessing over. If it's impressive, maybe I'll be in a good enough mood not to kill you."
He looked every bit the village thug tormenting an old man.
Shinnō staggered to the central pillar of the hall, gasping for breath. With trembling hands, he scraped along its surface, revealing a hidden compartment inside.
From it, he pulled out a scroll and tossed it at Kiyosuke.
"That's my technique," Shinnō said. "And also the method to control the Zero-Tails. It's one of the secrets I stole from Konoha. If you'd been there back then, I would never have managed to steal it."
So the Third Hokage's Telescope Jutsu—could he maybe not spend every day spying on the women's bathhouse?
And just how many dangerous forbidden jutsu did Konoha still have lying around?
While Kiyosuke was speechless at the thought, Shinnō pressed a hidden switch inside the compartment.
A trapdoor opened beneath his feet, and he dropped straight through.
Kiyosuke pocketed the scroll and turned to Sakura.
"Sakura, take that girl and go help evacuate the villagers. I'll blow this place up once we're done. Naruto, Sasuke—you're coming with me."
"Got it!"
"Let's go!"
They split up. Kiyosuke led the two boys into the mechanism below.
They descended into a cavernous chamber. Strange sealing runes covered the walls, and at the center hung a pale yellow cocoon. Inside of it—was the Zero-Tails.
"So it's here. This thing should be destroyed."
Kiyosuke's voice was firm.
But Shinnō, bloodied and battered, looked at them with smug confidence.
"Idiots! You're all fools! You actually came here yourselves! Asakawa Kiyosuke, you've walked straight to your death!"
"What?" Kiyosuke flared up with chakra flames in his hand, but the fire was instantly absorbed by the Zero-Tails.
Shinnō sneered, "You can't use ninjutsu here. The Zero-Tails devours chakra!"
"Then that means you can't use it either, right?" Naruto asked.
"So what? You young brats never understand!"
The cocoon around the Zero-Tails sprouted pale yellow tentacles that immediately dragged Shinnō inside.
"Your death is coming!" he roared.
Merging with the Zero-Tails, he unleashed countless tendrils, lashing toward Kiyosuke and the others.
Naruto and Sasuke quickly leapt back.
Kiyosuke, however, didn't dodge. He allowed himself to be seized.
Shinnō's voice echoed from within the Zero-Tails' body.
"What's wrong? Frozen in fear? Without your precious abilities, you're helpless! Did you really come here just to die? I won't let you off so easily! Your chakra will fuel the fortress of Ancor Vantian—the ultimate weapon that can wipe out the Five Great Nations!"
The Zero-Tails converted Kiyosuke's chakra into power. A blazing beam shot from the cannon mouth like lightning, instantly obliterating a mountain peak. It streaked across the sky, leaving a blinding scar of white mist over the ocean where seawater had evaporated from the sheer heat.
"W-what the hell?!"
On the shoreline, Kakashi and the others flinched in shock, unable to comprehend what had just happened.
Meanwhile, Shinnō reveled in the chakra flooding through him.
"This power…! Ohhh, it's magnificent! Asakawa Kiyosuke, your strength truly is Konoha's greatest! OHHHHH!"
"You think you can just swallow my power?"
Kiyosuke's body erupted with senjutsu chakra, surging straight into the Zero-Tails' maw.
"Are you insane? I'll gladly accept this! Wait—no, what's happening?! This sensation… AAAAAH! MY BODY!!!"
Shinnō shrieked in agony.
Kiyosuke laughed darkly.
"You thought attaining Sage power was easy? Every bone in my body had to shatter before I could endure it! Did you think just anyone could handle that pain? What will you use to withstand my power?!"
The Zero-Tails had no bones, but the Sage power seared through its body all the same. Shinnō, fused within it, bore the same torment.
Kiyosuke's chakra poured endlessly into the beast, forcing it to consume more than it could handle.
"I found it."
Sasuke's Sharingan zeroed in on a weakness in the Zero-Tails' seal.
He instantly transformed into his Cursed Seal Second Level form, black wings sprouting behind him like monstrous hands. Using their strength, he pierced the seal directly.
The barrier shattered.
The Zero-Tails' wormlike body smashed into the wall, writhing in pain.
Shinnō was expelled from within it, stumbling out even more withered and aged than before.