If Hatake Sakumo's soul could have seen this moment, he would've been shocked enough to shatter on the spot.
Kato Dan—a name that still represented grief for many.
Like Nawaki, he had once been one of Tsunade's most precious people, one of the few who had ever touched her heart.
And yet, this man—serene as moonlight—was walking side by side with Aizen Sōsuke, as though they had known each other for years.
Their steps echoed softly along an ancient-looking stone corridor, lamps flickering against the walls as they moved.
"Must you really use such methods?" Dan asked quietly, as if making casual conversation. "To provoke a soul with obsession and emotion just to make it maintain self-awareness?"
"There's no other choice," Aizen replied evenly. "Sakumo-kun is still unstable. He'll need at least twenty-one soul-surgeries before reaching equilibrium. Abandoning the experiment now would be wasteful, wouldn't it?"
"Using his son as leverage, though—that's a bit much."
"The souls of suicides are fragile and easily lost," Aizen said calmly. "Sometimes, a well-meaning lie is necessary."
Hands tucked into his sleeves, Aizen continued forward at a measured pace.
Their conversation drifted easily between them—but the shadows told another story.
For all their words and movement, only Aizen cast a shadow on the ground.
Under the light, Dan's presence was pure and transparent—no shadow, no substance.
—
"Thinking about it now," Dan murmured, his voice gentle but edged with curiosity, "you've always hinted that you're different from the rest of Konoha, haven't you?"
Without breaking stride, the shadowless man continued beside him. "The haori you wear isn't regulation issue. You never once donned a Konoha forehead protector. You never call yourself a shinobi—and your actions are rarely those of one. I remember Lord Third used to be quite troubled by you."
Aizen chuckled softly. "From a certain perspective, that's true. I'm not very good at pretending to be something I'm not. Quite embarrassing, really."
Dan smiled faintly. "If you'd just say what you truly think, many things would be easier to understand. Why always speak in circles, Aizen?"
"Because shaping a worldview," Aizen replied, "can't be done with a few words, Dan-kun."
They stopped before a sealed steel door embedded with biological locks. Aizen placed his hand upon the panel.
With a muted hiss, the massive gates slid open to either side. Dan followed.
The doors closed behind them almost instantly—bisecting Dan's form. But his body merely shimmered, phasing effortlessly through the barrier as though matter itself could not restrain him.
Neither man found this unnatural. They simply kept walking down the corridor as each light flickered on in sequence, illuminating their path.
Aizen's voice echoed, low and resonant—possessing that hypnotic, commanding tone only he could manage.
"Building a worldview takes time. Only by watching this world twist under the hands of the unworthy can one develop the will to resist."
"So that's why you wait until after death?" Dan asked. "While the living struggle to guess your intent, you wait for the dead to see the truth?"
"Yes."
Aizen's answer came without hesitation.
"You can't be blamed for what you believed in life. People are creatures shaped by their surroundings—misled by information, blind to reality. Only in death, freed from the cravings of the flesh, can one truly see what binds them."
"Love… or lust. Compassion… or ego. Do others act from sincerity or pretense? These truths are visible only when stripped of life's illusions. Most never see them even after death—content to drown in ignorance."
Aizen's warm smile returned as his eyes drifted toward Dan.
"For example—you once wanted to become Hokage. Yet now, even knowing what I've done, you've told no one. You've matured, Dan-kun. I'm genuinely pleased."
"…Even if I wanted to warn them, could I really deceive you?" Dan asked with a small sigh.
"Whether it's Sakumo-kun or you, Dan-kun, each of you is a valuable test subject. Remaining as you are suits me perfectly."
"So that's a 'no' then."
Dan exhaled softly, his tone weary. "When will we finally step out of the shadows, Aizen? When will we be free to stand beneath the sun?"
"Patience," Aizen replied, giving a small wave to the corridor sensors. "Don't rush. The time will come."
Layer by layer, doors ahead unlocked and opened.
Hands still tucked into his haori sleeves, Aizen continued in his calm, deliberate tone.
"The Soul Materialization Project is progressing well. The next phase involves imprinting and compressing the soul's residue. The forging of the Zanpakutō has begun—I've selected potential materials. Soon, through a proper medium, your souls will be able to manifest your true selves."
Dan's brow furrowed. "Why are you so cautious—so afraid—of chakra, Aizen?"
"Oh?" Aizen smiled faintly. "Why do you think that?"
"Your methods rely on manipulating natural energy to suppress reiatsu—on forging Shinigami bodies that merge nature and soul. The Zanpakutō channels self and spirit through resonance. All of it avoids chakra completely. I can understand your distrust of Konoha, but why reject chakra itself?"
Aizen's tone remained gentle. "It's merely prudence. To carve a new path, one must abandon old thinking—don't you agree?"
"…So we're still not trusted, then."
"Trust and reliance are twins," Aizen replied, adjusting his glasses. "They both belong to the weak. The moment you entrust your ideals to others, you lose them. I have no need for that. Besides…"
He glanced ahead at a chamber veiled in sealing tags and containment fields, his tone deepening.
"If I can craft Shinigami Contracts to observe and guide you, then doesn't it stand to reason that the one who created chakra might still be watching us too? If the world truly is his garden, what does he think of its ruin?"
Dan froze. His normally calm face stiffened with shock.
"…You can't be serious."
"Just a friendly warning," Aizen replied pleasantly. His smile, bathed in the sterile light, was as pure as ever.
"I neither affirm nor deny it. I only hope you'll all stay calm. I'd hate for my precious test subjects to get… damaged. Tracing chakra's origins is far beyond my scope. My current goal is much smaller."
"Smaller?" Dan gave a hollow laugh. "You call reviving the dead and showing them this world small?"
"It is," Aizen said lightly. "All I wish is to loosen the rot of this broken system, just a little."
At the corridor's end stood a final door.
Aizen pushed it open.
Inside lay several obsidian coffins, each pierced with tubes and wires pulsing faintly.
On one, engraved in pale silver, was a name: Kato Dan.
Aizen turned toward his spectral companion, his smile soft and genuine.
"When a fish tank is too small, the big fish suffocate. One must either expand the tank… or remove the other fish. Personally, I prefer not to kill the fish."
"…That's so very you," Dan muttered, shaking his head. He started to speak—but stopped as his hand darkened, a shadow dripping from his fingers and spreading across the floor like ink.
"Looks like my time's up," he sighed. "I don't fully understand what you're planning, Aizen… but please, don't take this too far. Many people are innocent."
"I'd never stoop so low as to harm the ignorant," Aizen replied softly. "Grow strong beneath Konoha's shade, Dan-kun."
As Dan's form began to dissolve, seeping into the coffin engraved with his name, Aizen adjusted his glasses once more, his voice filled with warmth.
"I'll be waiting for the day you all betray me—the shinobi of Konoha. But until then, I do hope you'll keep learning."
"If there's anything you don't understand," he added, smiling faintly, "feel free to ask. I'd be happy to enlighten you. After all, when you perform a monologue in a world no one understands, it can get… lonely."
At those words, Dan's fading form paused, as if wanting to respond—but his soul fully melted into shadow.
---
Aizen Sōsuke.
A mysterious man.
Always polite, always sincere—but never transparent.
Even to the dead, he revealed only fragments.
Under his white haori was the black inner lining of secrecy. Though a Konoha shinobi by title, he never wore a forehead protector or flak jacket. And yet, everyone who met him liked him.
Still, among the living, none truly knew who he was.
Even the dead had only glimpsed the tip of the iceberg.
"Sleep well, Dan-kun," Aizen murmured.
"And to everyone else—rest peacefully. You each have someone who loves you, so please, don't do anything reckless."
He gazed at the coffin as the last remnants of Dan's spirit faded into shadow. The serene smile on his face never wavered.
After ensuring all instruments were functioning properly, he turned and walked away.
The hem of his white haori slowly disappeared into the darkness.
The coffins remained silent—motionless, lifeless, as if nothing had ever been there at all.
---
Hours later, in the endless darkness, a quiet sigh finally echoed.
"Aizen Sōsuke… What did you see in this world that made you become this way?"
The voice was soft—gentle, sorrowful—
and it did not belong to Kato Dan.