The moment Tsunade heard the Kyūbi's voice ring with urgent demand inside the seal, she didn't hesitate.
Her body moved in a blur, tearing across the forests and rooftops with chakra-enhanced speed. Trees whipped past. The air screamed in her ears. Her arms clutched Naruto tightly as blood continued to trickle from his wounds, his breathing shallow.
"Shizune!" Tsunade's voice thundered as she landed at the hospital gates. "Bring me the sealed scroll from the Senju Treasury—the one marked with the clan crest!"
Shizune, already pale with worry, nodded and disappeared in an instant, her footsteps light but frantic as she raced toward the old vaults deep in the Senju estate.
Inside the emergency room, Tsunade worked with clinical precision. Her haori already lay discarded. With Naruto laid on the primary operating bed, she summoned a sterile blood-sealing kit from a side table and immediately began extracting blood from her own arm, which belonged to same blood-group.
He'd lost too much. Her blood wouldn't just replenish it —it would stabilize, giving him the immune support needed to buy time.
Shizune reappeared just as the blood bags were filled, clutching a long, dark scroll bound with intricate red and gold sealing ink.
"Seal the operating chamber,"Tsunade said curtly. "We begin now."
Tsunade pressed her palm to the scroll. It glowed, unlocking the senju cellular matrix and held within, embedded in its innermost layer was the biological core—the living cell sample of Hashirama Senju himself. Her chakra surged as she activated the primary transfer seal, and then carefully—meticulously—channeled it into Naruto's stomach where the Five-Element Seal had been broken. Hashirama cellular regeneration—an ability so profound no modern medical science could fully replicate—was the backbone of this transfer. As Tsunade infused the Hashirama cell lines into Naruto's failing body, she did not graft them to dominate, but rather to harmonize.
Tsunade injected her prepared blood into the transfusion line as she guided the cellular transfer forward. Her chakra was threaded with every drop—pushing the cells to knit with Naruto's damaged tissue. Not overtaking. Supporting.
Soon a warm, eerie red glow erupted from his body.
Kyūbi's chakra flooded out, snaking through the air like mist—slowly blanketing his limbs, his spine, his heart. It wasn't violent. It was protective. Stabilizing. Bonding. Its form, half-faded and shimmering like smoke, flared back to life—not fully, but enough. Sensing that Tsunade's medical techniques had bought Naruto precious time, the Kyūbi released a final burst of regenerative chakra into Naruto's core.
The senju cells began merging with Naruto's natural tissue. The structure of his organs, bones, even chakra pathways began adapting—not violently, but with eerie fluidity.
[Inside the seal]
Naruto's consciousness floated in blackness.
He opened his eyes slowly to find himself in the sewer-like prison of his mind—the great iron gates before him. The water at his feet was dark and sluggish, and his body was translucent.
"W-what is this?"Naruto murmured, staring at the endless black around him. "Am I… dying?"
A massive eye snapped open behind the bars, casting an eerie glow across the seal. The Kyūbi's snout emerged from the shadows—not snarling, not seething with hatred—but silent. And still.
Naruto froze. It was the first time he had ever seen the creature sealed inside him—the Kyūbi, the Nine-Tails.
"You're not dying," fox rumbled, its voice deep.
"You were close. Too close," Kyūbi continued, its tone strange—less angry, almost… resigned. "That snake's poison nearly ended you… but you will live. The woman… Tsunade… she gave you more than her blood. She gave you another chance."
Naruto blinked. "Why? Why would she go that far for me?"
The fox's massive eye half-closed, as if tired.
"Because she sees it. The same thing I saw—once. You're not just saving friends or protecting your village anymore. You've started reaching beyond borders. Other lands—Kaigan and Land of Waves , other hearts… like that boy of sand. You didn't defeat him. You changed him."
Naruto stood still, absorbing the words. The red mist curled around his feet.
The Kyūbi exhaled slowly, and the space within the seal seemed to dim.
"Maybe," the fox whispered, "just maybe… you'll be the one the Sage dreamed of. A world where jinchūriki don't have to be born. Where biju dorsn't have to suffer. Where power… isn't a curse."
The bars around the cage shimmered, and the light within the seal flickered.
Naruto stepped forward, eyes wide. "Wait… why are you saying this like—"
The Kyūbi's form dimmed further, the edges of its massive body unraveling like smoke.
"I gave everything I had to keep your body alive," the fox murmured. "More than I should have. The regeneration, the fusion—it drained what was left of me. The seal held, but my chakra... I used the last of it."
Naruto's breath caught. "No… no, wait. You can't—"
The red mist lifted completely. Naruto felt the ground beneath him again, warmth trickling back into his chest.
"Maybe… this isn't the end. I'll return, one day. One way or another."the Kyūbi said, its form fading behind the bars.
"I just… didn't want to end up alone," Naruto said, his voice quiet but steady.
The fox's last glowing eye lingered on him.
"You never were. And you won't ever be."
With that final whisper, the Kyūbi's form disintegrated—fading into motes of red light that sank into the seal, the cage dimming until only the faint spiral of the Uzumaki crest remained glowing at Naruto's feet.
[Meanwhile]
What was not expected… was the awakening.
Deep within Naruto's body, something stirred—long silent, long dormant.
The Ōtsutsuki genetic cell, buried deep within Naruto's genetic makeup, a remnant from the battle with Ranmaru, had been inert—biding its time in the deepest recesses of his being. It had survived unnoticed, too alien for normal chakra scans, too still to react to normal stress.
But now, sensing the Kyūbi's waning presence, the flood of Hashirama's cell, and Tsunade's life-bound chakra, the alien cell reacted.
It awakened.
The fusion wasn't explosive—but biological.
Chakra pathways widened. His internal network surged with new potential. The regenerative abilities skyrocketed—accelerated beyond even what Tsunade had prepared for. The Ōtsutsuki fragment didn't replace Naruto's humanity—it intertwined with it, enhancing his potential abilities.
[In Operation Chamber]
Naruto's body began to glow faintly, the red chakra of the Kyūbi dancing gently along his skin, mingled with golden threads—barely visible, but pulsing with ancient, otherworldly rhythm.
"Shizune…" Tsunade said quietly, watching the boy's body stabilize in a way no ordinary human could. "He's past the danger. His vitals… they're not just recovering—they're evolving."
Shizune looked at her in awe, still monitoring every line, every chakra fluctuation. "Is it because of Hashirama-sama cells?"
Tsunade shook her head slowly. "It's… more. Something else in him responded to it. Something odd."
She turned away from the table, her exhaustion showing now that the worst had passed. Her hands dropped to her sides as she looked toward the reinforced chamber doors.
"The operation's done. But Naruto is still in coma," she said, her voice hard. "No one enters this chamber—not until I say so. Not even the Hokage's advisors. Understood?"
Shizune nodded, sealing the chakra barrier tightly behind her mentor.
Tsunade gave one last look over her shoulder at Naruto—his body quiet now, but visibly glowing with a blend of red, gold, and subtle green chakra from her own blood. His chest rose and fell, slow but strong.
Then she turned and left the sealed room.
Outside, the chaos of the village still needed her.
But in the depths of the hospital, behind reinforced walls and ancient chakra seals, something far more important was unfolding—the rebirth of Naruto Uzumaki, not as a mere shinobi, but as something new… something with the potential to reshape the legacy of ninja-world forever.