Because the sealed space within Uzumaki Naruto was originally created by Namikaze Minato, there was no need for any so-called key. The moment Minato unsealed it, a burst of fiery red chakra surged forth from Naruto's body.
This chakra was unlike anything Naruto had ever felt before—wild, untamed, and brimming with negative emotions. It carried a deep, ancient resentment, as if it had been caged for centuries, yearning to break free.
Yet, just as quickly as it appeared, the chakra shrank back, retreating into the depths of the seal as if it had never been there in the first place. Naruto blinked in confusion, barely able to register what had just happened.
"Father... what was that just now?" Naruto asked, his voice uncertain. "For a moment, I felt a huge amount of chakra inside me, but then it just... disappeared."
Namikaze Minato reached out and gently patted Naruto's head, his expression soft yet serious.
"Nothing to worry about, Naruto," he reassured. "Inside you lies a great power—one that I sealed away long ago. Its name is Kyuubi, the legendary Nine-Tailed Beast. And soon… I will take you to meet it. You two must learn to coexist. With the Kyuubi by your side, your strength will surpass your limits."
Naruto hesitated for a moment before nodding in understanding. Whatever this "Kyuubi" was, he would face it head-on.
Everyone present gathered their chakra, preparing to enter Naruto's sealed space. Even Uchiha Sasuke and his family, along with Haruno Sakura, followed suit, their curiosity piqued.
Inside the sealed space, the Kyuubi was far from pleased.
No—"unhappy" was an understatement. It had spent its entire life in a cycle of entrapment, betrayal, and endless confinement. The moment it sensed the presence of humans, it narrowed its eyes in deep irritation.
From the very beginning, its fate had never been its own.
It remembered the days when it roamed freely with its nine siblings.
The grass was lush, the flowers fragrant, the sky endless, and the air crisp and sweet. Life was simple. When boredom struck, it could release a Tailed Beast Bomb and watch the mountains crumble for entertainment.
But then… that man appeared.
A man with burning red eyes, eyes that swirled with a cursed power.
Uchiha Madara.
At first, the Kyuubi had scoffed at him. A mere human daring to challenge the strongest of the Tailed Beasts? Laughable. But then, with a single glare from those wretched eyes, everything had changed.
It had lost control.
It had become nothing more than a weapon in the hands of an accursed Uchiha. And worse… it had been forced into battle against an even more terrifying monster.
Senju Hashirama.
The Kyuubi had not feared many things in its existence, but that day, for the first time, it had known what it was to be truly powerless.
The Kyuubi still remembered the arrogance it had once held, the confidence that no one could ever best it. With the mighty Susanoo clad over its body like armor, it had felt invincible. At that moment, it had believed that even the Sage of Six Paths himself would fall before its power.
And then, Hashirama had simply clapped his hands together.
A thousand-armed giant of unfathomable power had descended from the heavens, and in the blink of an eye, the Kyuubi's arrogance crumbled beneath an onslaught of relentless strikes.
It had fought with all its might.
But in the end, it had been struck down. Crushed beneath an endless barrage of wooden fists, unable to so much as roar in defiance.
The humiliation had been unbearable.
And then came the worst part.
As the battle ended, Hashirama had stood before its battered form, his expression solemn yet firm.
"Your power is too great," he had declared. "For the sake of this world, I must seal you away."
The Kyuubi had been furious.
"Too great?"
He had watched that man summon a godlike entity, a behemoth that dwarfed even the strongest of Tailed Beasts. He had witnessed the impossible power of the Senju.
And yet, Hashirama had the audacity to claim that he was the one who was too powerful?
"If I am too strong… then what does that make you, Hashirama?!" the Kyuubi had wanted to roar.
But it hadn't mattered. The decision had been made.
From that moment, its nightmare only continued. Defeated and sealed, it was stripped of its freedom and placed within Hashirama's wife, Uzumaki Mito.
The Kyuubi had sworn to break free.
It had waited for Mito to weaken, for the seal to loosen. It had plotted, seeking the right moment to unleash its fury upon the world once more.
But Mito… was not weak.
With her accursed golden chains, she had bound it without effort, rendering it powerless.
Time passed. Decades faded away.
Then, just as Mito's life came to an end, a new prison awaited—the belly of another woman. Uzumaki Kushina.
The Kyuubi raged, refusing to accept this fate. Surely, this one would be weaker! Surely, he would escape!
And yet, once again, golden chains wrapped around him, binding him like a mere pet.
The humiliation deepened.
All he could do was wait.
Wait for the day when Uzumaki Kushina's life would also fade.
And then came the night of freedom.
Or so he had thought.
The moment he had been released from his prison, he had once again fallen prey to those wretched crimson eyes. Controlled. Manipulated. Forced to do battle once more.
But this time, his captor was not Madara.
It was a man bearing the same cursed eyes—a masked Uchiha.
Before the Kyuubi could even fully revel in its brief taste of freedom, Namikaze Minato had intervened, dragging him back into yet another prison.
And as if that wasn't enough, the man had split him in half.
Half of him was sealed away with Minato, never to be seen again.
The other half… remained locked inside the boy.
The Kyuubi sneered at the cruel fate that had cursed him. Even now, as he sat within the depths of the seal, he could feel those damn golden chains restraining his movements.
How many times had he endured this? How many times had he been caged like a beast?
Even the thought of it made him seethe with rage.
His so-called "hosts" came and went, but his suffering never ended.
And now, here they were again. Humans.
The Kyuubi growled, baring its massive fangs as it glared at the figures stepping into its domain. Its crimson eyes burned with hatred, yet beneath that hatred was something deeper—exhaustion.
He was tired.
Tired of being used. Tired of being caged.
And most of all… tired of humans.
Yet, as the golden chains around him tightened ever so slightly, he knew one thing for certain.
No matter how much he despised this fate, there was no escaping it.
Not yet.