Sarutobi Hiruzen stood before the gates of the underground base, his form draped in battle armor, the adamantine staff Enma resting firmly in his hand.
Shrouded in shadow, the entrance exhaled a heavy, oppressive silence. Hiruzen took a deep breath.
He had received word a year ago that Orochimaru might have restarted the forbidden Wood Release human experimentation.
At that time, however, for the sake of postwar stability—or perhaps out of his own indulgence toward his most gifted and beloved disciple—Hiruzen had chosen to quietly allow the research to continue.
He had only sent a few ANBU to keep discreet watch over Orochimaru's activities.
In the beginning, it seemed tolerable. The research, though unethical, had yet to cross his ultimate line: Orochimaru's experiments had not yet targeted Konoha's own shinobi.
But long-suppressed desires always erupt with sudden violence. And now, that explosion had borne its bitter fruit.
Four days ago, Hiruzen had received news that the ANBU monitoring team had been found dead.
As he began a preliminary investigation, new reports arrived—members and heirs of several bloodline clans, as well as elite jōnin from civilian families, had all gone missing.
Within mere days, immense political and social pressure had forced his hand. He could no longer delay, no longer hesitate.
And now, they had finally located Orochimaru's base.
The Third Hokage, who had once led Konoha to victory in two great ninja wars, looked upon the darkened gate before him, and his eyes fell low.
"Orochimaru…"
"Why must it come to this?"
But no matter what turmoil churned within his heart, Hiruzen knew there was no turning back.
Composing himself, he turned to the ANBU assembled behind him and spoke in a calm, solemn tone.
"Breach the base. Apprehend the traitor Orochimaru."
"Life or death—does not matter."
"Yes, sir!"
At his command, the ANBU moved in unison. In perfect formation, the infiltration squad breached the doors and filed swiftly into the depths.
Though the Hokage himself was their leader, Hiruzen charged at the front of the formation. With Enma in his hands, he shattered obstacle after obstacle, clearing the path downward.
Whether out of the instinct to protect the young ANBU under his command, or out of a deeper, unspoken sentiment buried within his heart, Hiruzen did not want these children to face Orochimaru directly.
All of this did not escape the keen eyes of Hatake Kakashi, who followed close behind.
Having spent so many years in the ANBU, Kakashi had long since learned to read the old man's true intentions through every word and gesture.
Seeing the Hokage's personal determination, he subconsciously relaxed a little.
He was already planning to take things easy—perhaps put on a bit of a show when the fighting began, a few flashy Raikiri strikes here and there, just enough to appear diligent.
But to his surprise, they met no resistance at all as they advanced deeper.
The abnormal silence tightened the air around them, and Kakashi's instincts began to stir uneasily.
The young Uchiha Itachi, walking just behind him, seemed to sense it too.
"Kakashi-taichō?" he whispered.
"Be careful," Kakashi replied quietly.
Boom—
The last iron gate fell under the crushing swing of Enma.
Sarutobi Hiruzen stepped forward, his face grim, entering the lowest chamber of the base.
But the sight that awaited him was not what he had feared. No gruesome experiments, no captives, no signs of Orochimaru at work.
The cold, sterile hall was littered with corpses—most dressed in white lab coats, evidently the research staff.
Only on one side of the hall was there a gaping breach, torn open as though something—or someone—had forced their way out.
"He was warned in advance, then…"
Hiruzen exhaled slowly, relief and sorrow mixing faintly in his chest.
Such was the way of the world.
As long as he had not caught Orochimaru in the act, both sides could still maintain a fragile illusion of peace.
Even if it was only self-deception.
For as long as there remained the slightest chance, Hiruzen could not bring himself to kill the man who had been like a son to him.
Age had made his hair white and his spirit weary—and with that weariness came compromise.
Just as he began to ease his tension, static crackled in his earpiece.
A distorted voice broke through the noise—urgent, panicked.
"Lord Third! Emergency report!"
"Source Leaf Town—three hundred households wiped out! Four ANBU and Root squads annihilated!
Traces of combat and Wood Release experiments everywhere! Seven Cloud-nin corpses found on site—no sign of the perpetrator!"
"Judging by the evidence, we believe… it was Orochimaru!"
Hiruzen froze where he stood, the blood draining from his face.
So in the end—there was no escape.
...
A brightly lit corridor.
Two figures—one tall, one small—walked side by side.
Behind the taller man, Kabuto followed stiffly, his steps measured and cautious.
At the front, Aizen strolled with calm ease, pushing open the heavy laboratory door with a quiet hum.
Inside, at the center of countless sealing layers, stood a cylindrical containment tank.
Within it, suspended in a clear, viscous fluid, floated a blade embryo—white as bone, its form unstable and shifting, yet unmistakably that of a sword.
"What a fascinating world this is," Aizen thought to himself as he gazed at the unfinished weapon.
Aizen Sosuke.
Former Captain of the Fifth Division, Gotei 13.
Former most-wanted criminal of Soul Society, sentenced to twenty thousand years in confinement.
Now—A Konoha jōnin. Head of the Third Research Division under the Hokage's office.
At times, the contrast between his past and present selves made even him feel disoriented. By his count, he had already lived in this world for twenty-two years.
But unlike his former life, where he was born with transcendent talent and intellect beyond compare, this time he had begun as an ordinary man.
No noble lineage. No bloodline limit. No miraculous awakening.
Just another common shinobi.
If not for a few… subtle manipulations, his strength would have been merely average.
The only fortune he possessed was the vast memory of his previous existence.
After years of patient research and quiet observation, he was finally nearing the first milestone of his grand design—
—to reforge a Zanpakutō.
The first and greatest obstacle before him was the enormous difference between the two worlds—their very laws of existence.
Unlike the previous world, whose Three Realms were built entirely upon the essence of spirit, structured upon the sacrifice of the Soul King, this world was governed purely by matter and energy.
Here, he had witnessed countless souls dissipate into nothingness—yet never once had he seen a Shinigami appear.
That alone was enough to tell him: this world did not possess Death Gods, not as an organized or natural order.
And yet—souls and spiritual energy undeniably existed.
In fact, the upper limits of power in this world far exceeded what most shinobi could comprehend.
Through decades of careful study—of ancient texts, gathered intelligence, and first-hand observation—Aizen had reached an astonishing conclusion.
Once, this world had known an entity of immense power: a being called the Sage of Six Paths.
He was said to have shared a mysterious energy called chakra with the inhabitants of this planet.
And that "sage" had not stood alone—he had a brother, Hamura, with whom he had battled a goddess named Kaguya and sealed her upon the moon.
It all sounded like myth, a fantastical legend—yet when measured against the bizarre reality of this world, the story became disturbingly credible.
More so when he confirmed that the man called Hamura truly existed, and was indeed the progenitor of the Hyuga clan.
Even now, the Hyuga seemed to maintain a secret connection with a people dwelling upon the moon itself.
At the same time, Aizen could sense that this world was being observed by something—an unseen will, or power—perhaps from the depths of the ocean, or beyond.
That was one reason he had never stepped fully into the light.
His strength, as yet, was far from sufficient.
For though this world had birthed beings capable of splitting mountains and reshaping the heavens, the power displayed by today's shinobi—even the Kage—was still a pale reflection of what once had been.
And so, to reach his next stage—to reclaim the power he once possessed—he needed to accelerate his progress.