"The research on the deification of death is finally showing some progress, and you will be the perfect test subject."
Aizen's voice was calm, almost tender, as he glanced toward the figure trapped within the light blue energy. The faint, flickering remnants of Sakumo Hatake's soul twisted and struggled violently against its restraints, but Aizen showed no concern.
"Oh, and don't worry about your son, Kakashi. I'll make sure to take care of him. He's an exceptional child—full of potential. I'm confident he'll become my most outstanding assistant."
Aizen's words carried an eerie tranquility, as though he were discussing a simple matter of fact. He paused, adjusting his glasses before continuing, "If all goes as planned, I will officially adopt him in three days. Imagine that, Sakumo. Your son—my foster child. Don't you think it's a marvelous arrangement?"
Sakumo's flickering form glared back at Aizen, fury etched into his spectral visage. Yet, no matter how desperately he thrashed within his prison of light, he couldn't break free.
The laboratory was a grim landscape of bottles, jars, and various organ specimens, all neatly displayed around the room. In the midst of this macabre setting, Aizen's presence stood out—serene, elegant, a man cloaked in a white haori, quietly writing calligraphy amidst the chaos. He exuded the same calmness as the soft moonlight, indifferent to the struggles of the broken soul before him.
Sensing Sakumo's rage, Aizen slowly pushed his glasses up the bridge of his nose and smiled, stepping closer to the cage that held his prey. His hands slipped into the wide sleeves of his haori as he moved with quiet grace, his voice soft yet cold.
"Good afternoon, Hatake Sakumo. Please forgive the dilapidated state of this place," Aizen Sōsuke said, his voice calm and polite.
Hatake Sakumo's eyes flared with anger as he gazed at the well-mannered man before him. The nightmare he had feared most in life had now become a grim reality.
"If you so much as lay a hand on him—I'll kill you, Aizen!" Sakumo roared, his soul trembling with fury.
Aizen's lips curved slightly, a cold, detached expression crossing his face. "Interesting. Do ninja souls who commit suicide often break free of their restraints like this?" He adjusted his glasses, which caught the dim light and reflected the shattered figure of Sakumo, his eyes filled with rage.
"It's peculiar, really. The difference between your soul and your living self is remarkable. I doubt the living Sakumo would react so passionately to this kind of stimulus."
He paused to observe Sakumo's trembling soul, a gleam of curiosity in his eyes. "The study of the soul… it's fascinating no matter how many times I delve into it. Each soul offers new insights, new directions for research."
'I'll kill—'
"Your anger is futile, Sakumo-kun. You're making sounds purely through the force of your will, but in this state, you are powerless. You can't do anything."
Aizen moved to the array of instruments surrounding the soul cage, casually adjusting buttons and pulling levers. A strange humming filled the underground space.
"I'm not toying with you. I'm serious about teaching your son. He's a genius, and I could use someone like him. It's lonely, you see, to be alone with my knowledge."
'You're unbelievable—'
"Believable or not, the facts remain unchanged. Your son will become my adopted child, Sakumo. Isn't this the outcome of your choice to die? When you took your life, did you really consider your child? It's almost laughable how people realize what they cherish most only after they're gone."
'—'
The soul fragment in the frame stared at Aizen, momentarily frozen. He had never truly thought about it that way.
A six-year-old boy, whose father—branded a traitor—chose suicide just before his graduation from the Ninja Academy. What kind of life will Kakashi face in the future? What kind of environment will he live in now? I chose to end my life to prove my innocence, and while that decision brings me peace, what about Kakashi? He's just a child, only six years old. His mother died during childbirth, and now… he's lost me too. What about Kakashi?
Hatake Sakumo's soul froze in the frame, overwhelmed by these thoughts. But Aizen, focused on his experiment, didn't give Sakumo any more time to dwell on his past. Instead, with cold precision, Aizen pressed a button, activating the massive machinery surrounding the frame.
Suddenly, light blue sparks began to crackle from both sides of the machine, filling the room with an eerie glow. Despite the soul being theoretically incapable of physical sensation, Sakumo let out piercing screams as the blue light coursed through him.
Watching the tormented soul of Sakumo Hatake, Aizen remained calm, his eyes focused on the data displayed on the screen. With one hand, he compared the incoming data to another screen, while the other hand adjusted the instruments, all the while speaking as if he were teaching a lesson.
"This is an important opportunity, Sakumo-kun. You're a very intelligent man, so I think it's only fair you understand your current state."
"The spiritualization technique, natural energy, and chakra—there is indeed a conversion mechanism between the three."
"It is possible to exist in this world purely as a soul, and even have a brand engraved upon it."
"To do this, however, you need a substance that can reflect the soul's distinct characteristics. This creates a refraction that allows the natural energy and the soul to interact. And the lubricant for this interaction isn't chakra as we commonly understand it, but rather our self-will."
"Isn't it fascinating? When self-awareness becomes strong enough, it can actually influence natural energy. Although chakra, the source of life, passively plays a role in this process, it is the ego—one's will—that truly drives it. My research began because of this idea of the ego."
"Knowledge of the world and knowledge of ourselves—that is what makes us unique, Sakumo-kun. You can only act when you will it. But even the mere act of thinking is itself an action. According to ancient legends, people could even harness the power of heaven and earth through meditation. Isn't that a wonderful concept?"
His gaze was almost completely condensed into a flame of anger. Enduring excruciating pain and torture, Hatake Sakumo forced himself to listen to Aizen's words, desperately trying to understand and analyze their deeper meaning. After all, he was a ninja. Once the initial fury subsided, he began to think more calmly, attempting to grasp the significance of Aizen's words. He could sense that Aizen was speaking about something crucial.
But each time he tried to focus, the light blue electric current surrounding him would tighten and compress, making it impossible to concentrate. He felt like an iron ingot cast into a forge, being repeatedly hammered and beaten by overwhelming forces, purging and erasing all impurities from his soul—especially chakra.
As Sakumo endured the most brutal torture imaginable, Aizen continued speaking in his gentle, almost story-like tone. His calmness was a sharp contrast to Sakumo's torment.
"Katō Dan. The one who mastered the Spiritualization Technique. I was deeply saddened when Katō Dan died… You should know this. There was no one in Konoha more valuable for research than him."
"The futile sense of responsibility and meaningless struggles led him to die at the hands of incompetent people. His dreams, his ambitions—they were inherited by others. But what does it matter? In the end, Kato Dan is still dead. And his girlfriend? Useless, except for her skills in medical ninjutsu."
"Ultimately, the human body is nothing more than this—a mere clay doll manipulated by chakra."
"But thousands of years ago, we weren't like this. Natural energy, the soul, spirituality, chakra… I've finally taken the first step. I've broken the boundary between body and soul. But I still need to test my theory."
"Theoretical verification is quite different from practical experimentation, and that's where you come in, Sakumo-kun. If you can endure, Kakashi-kun will be very pleased."
"Come on, I'm on your side. I may very well be the last person in the world who doesn't want you to disappear."
'Aizen... Sōsuke!!!!'
"Still haven't calmed down? How unfortunate. Your complete disappearance would signify the failure of a path. What a sad outcome that would be. You must survive, Sakumo-kun."
Looking at the soul, which was almost fully unrestrained within the frame, Aizen smiled gently and pressed the button on the machine. A brighter light immediately flooded the room, causing Hatake Sakumo's soul to be swallowed by the countless rays of light, rendering his screams silent. Aizen, however, harbored no malicious intent. After confirming that Sakumo was no longer capable of coherent thought, he casually set the machine's timer and left the testing ground.
As he stepped into the corridor, he was stopped by a figure leaning against the wall.
"You still enjoy playing the villain so much, Aizen."
"Oh, that's quite true. Now that you're here, do you have any advice for me?"
Pushing his glasses up his nose, Aizen turned to face the long-haired man standing in the corner with his arms crossed, a peaceful expression on his face. Aizen's own smile remained warm and inviting.
"The soul materialization experiment is still unstable. If it proceeds too recklessly, there's a real chance the subject could be assimilated by natural energy or chakra. From my personal recommendation, you should take it slow."
"I feel fine, actually. I just came out to read a book and get some fresh air. You don't mind, do you?"
"Did you sense the arrival of a new soul?"
Aizen's smile grew even kinder and more sincere as he looked at the man with moon-white hair, quiet and elegant yet radiating a mysterious, unyielding will.
"As usual, you can't lie, Duanjun. You're such a gentle man. Did you sense the presence of an old comrade's soul? Is that why you came out to dissuade me?"
"I can't deny it," replied the figure, who had once been the object of admiration in Konoha.
Kato Dan, the Konoha Jonin who mastered the Spiritualization Technique and had done extensive research on life, death, and the soul, stood before Aizen Sōsuke. He should have perished long ago from his internal organ injuries, yet here he was, standing in this dim corridor, confronting Aizen.
However, rather than exchanging hostilities, Kato Dan sighed as he slowly walked toward Aizen, joining him at his side.
"After all, I just don't like this method."
Both Kato and Aizen, men who should have been long dead, strolled side by side through the corridor, like old friends.