Fifth Division, barracks.
Unlike the Third Division's quarters by the water, the Fifth Division's quarters were built directly on the water, not just a single building, but a cluster of wooden houses, each of a different design.
The wooden houses were connected by roofed walkways, forming a secluded paradise upon the water. The environment was pleasant and the location not too remote, yet it carried an inexplicable sense of tranquility, putting people at ease.
At this moment, in the Captain's office of the Fifth Division's quarters, Sōsuke Aizen, wearing the white haori of a Captain, was seated at his desk, holding a brush and carefully writing something.
The room was extremely quiet. Other than Sōsuke Aizen, there was no one else present. Yet, as if time and space had suddenly distorted, a moment came where, without any sign or warning, another figure appeared before Aizen as though it had always been there.
"What a rare guest."
Aizen didn't look up, didn't even stop moving his hand. A smile remained on his face as he spoke.
"For Captain Kaiser to visit personally, I believe this is the first time, isn't it?"
The figure who had appeared before Aizen was indeed Kaiser.
"Is Captain Aizen reproaching me?" Kaiser sat down nonchalantly across from Aizen, as though he were an old friend, pouring himself tea from the pot on the side and saying calmly, "But you haven't visited the Third Division's quarters either, have you? Not even once!"
"Is that so?" Aizen still didn't look up, smiling. "Maybe it's just that you never noticed."
"That's true." Kaiser nodded with mock seriousness, raised the teacup, and took a sip. "With Captain Aizen's skill, sneaking into the Third Division's quarters unnoticed would be a piece of cake."
"Forget the Third Division—even Central 46 probably couldn't stop your steps."
Kaiser's relaxed and casual remarks would've caused an uproar had anyone else heard them.
Yet the ever-gentle Aizen didn't offer any denial.
"You've always been this way," Aizen said with an implied meaning. "Even though I've shown you nothing but kindness, you've always kept a vague yet persistent wariness toward me."
"Always projecting a free and easygoing image, yet you occasionally reveal an unexpected insight, as though you see through everything."
Aizen finished writing, set the brush aside, looked up, and gazed at Kaiser.
"I'm quite curious. Why are you like this?"
"Did you happen to meet people who should no longer appear in Soul Society, and learn something from them?"
"Or… have you been one of them from the beginning?"
For those unaware of the inner truth, Aizen's words would've sounded baffling.
But not for Kaiser.
"By 'them,' do you mean Urahara Kisuke? Or the Visored?"
Kaiser's calm response made Aizen look at him deeply.
"So you do know them."
Aizen's smile remained gentle.
"I've indeed looked into them."
Kaiser's reply carried layers of meaning.
Over a hundred years ago, the Gotei 13 was not what it is today.
At that time, the former Captain of the Third Division was still alive, Aizen was still a Lieutenant, and Gin Ichimaru had only just emerged, not yet famous.
Back then, a major incident had shaken all of Soul Society.
At first, only souls from Rukongai were mysteriously vanishing. Later, even Shinigami began disappearing, prompting serious attention from the Gotei 13 and leading to several Captains and Lieutenants being dispatched to investigate.
As a result, during the investigation, the former Captains of the Third, Fifth, and Seventh Divisions, the former Lieutenant of the Eighth Division, the former Captain and Lieutenant of the Ninth Division, the former Lieutenant of the Twelfth Division, and the former Deputy Chief of the Kidō Corps—eight in total—were all caught in the incident and began undergoing Hollowfication.
These top-level Shinigami of Soul Society were transforming into Hollows, which naturally caused an uproar throughout Seireitei.
Afterwards, Central 46 declared that the former Captain of the Twelfth Division had orchestrated a Hollowfication experiment, victimizing several Captains and Lieutenants, and sentenced him to death. Those affected by Hollowfication were also treated as Hollows and sentenced to execution.
At a critical moment, the former Captain of the Second Division broke into the courtroom, rescued everyone, and escaped.
Since then, the Gotei 13 was left with many vacant positions. Genryūsai Shigekuni Yamamoto began heavily promoting talent, appointing capable Shinigami to Captain and Lieutenant roles.
That was when Aizen became Captain of the Fifth Division and promoted Gin Ichimaru as his Lieutenant. Kaname Tōsen became Captain of the Ninth Division, Suì-Fēng became Captain of the Second Division, Sajin Komamura became Captain of the Seventh Division, and Mayuri Kurotsuchi became Captain of the Twelfth Division. Only the Captain's seat of the Third Division remained temporarily vacant due to a lack of candidates; the other positions were filled gradually.
The "Urahara Kisuke" and "Visored" Kaiser referred to were the victims of that incident.
Urahara Kisuke was the former Captain of the Twelfth Division, declared by Central 46 to be the mastermind behind the Hollowfication experiment.
The Visoreds were the group of affected Captains and Lieutenants who banded together.
Their existence had become something of a taboo in Seireitei. For over a century, almost no one had dared mention them.
But Kaiser, who only arrived in Soul Society after that incident, casually revealed their existence.
"I heard you were still the Fifth Division's Lieutenant back then," Kaiser looked at Aizen with a detached gaze and said, "Who would've thought that a mere Lieutenant was secretly orchestrating the Hollowfication experiments, turning several Captains and Lieutenants into test subjects?"
"Of course, that was hardly your only scheme."
"Decades ago, the Hollow I encountered during my training in the World of the Living was your doing. That attack was your plan."
"Over twenty years ago, you also orchestrated the disappearance of the former Captain of the Tenth Division, Isshin Shiba, nearly killing him in the World of the Living."
"This time, you planned the execution of Rukia Kuchiki."
Kaiser set down the now-empty teacup and slowly addressed Aizen.
"To think the one who plotted all of this, who manipulated so many conspiracies behind the scenes, is the universally admired, gentle, kind, and friendly Captain of the Fifth Division… If word got out, no one would believe it."
At this, Aizen pushed up his black-rimmed glasses and chuckled softly.
"So, is that why you came to see me alone?"
Because no one would believe him, he had to do it himself.
Because there was no evidence, he had to bear the burden alone.
"You're more responsible than I thought, Kaiser-kun."
Aizen used the nickname from their Shin'ō Academy days.
But that only made Kaiser scoff.
"You think I came here to stop your evil schemes?"
Kaiser laughed as if hearing a joke.
"Isn't that why you came?"
Aizen's smile didn't fade.
"Of course." Kaiser's smile deepened. Then he said, "I only came here for one reason."
"To take a little revenge for that year."
As those words left his lips, another figure of Kaiser appeared behind Aizen.
Just as he had done when facing Suì-Fēng, this second Kaiser reached toward Aizen's shoulder, seemingly about to grab it.
Reiryoku swirled around his palm, causing the seated Kaiser in front of Aizen to become faint like a lingering afterimage.
Just as Kaiser's hand was about to touch Aizen's shoulder, he suddenly stopped.
"Clang!"
With a sharp sound of clashing metal, Kaiser's glowing hand abruptly lifted and collided with a sharp, indiscernible weapon—sparks flying.
"Whoosh!"
A slicing wind struck from Kaiser's other side, carrying a blade's edge sharp enough to sting the skin.
"Shhk!"
The Kaiser who had been raising his hand was split in half by the unseen strike, his entire body blurring once again.
"Hm?"
Only now did Aizen's eyes shift as he looked up.
"Scattered bones of beasts, spires, red crystals, wheels of iron, the wind moves, the sky is still—the sound of spears clashing echoes through the empty castle!"
Kaiser had appeared above, on the ceiling, standing upside down as if walking on flat ground. He extended his palm toward Aizen below.
Dazzling lightning flashed in his hand.
"Hadō #63: Raikōhō!"
Lightning burst forth, flooding the room.
"BOOM!!!"
A wooden building of the Fifth Division, standing on the water, exploded with a thunderous roar, bolts of lightning shooting outward.
This massive disturbance naturally drew the attention of nearby Shinigami.
"Enemy attack!"
"Enemy attack!"
"Is it the Ryoka?!"
"It's coming from the Fifth Division's barracks!"
"Get over there!"
Nearby Shinigami, drawn by the commotion, rushed over with torches in hand.
"Something's wrong! It's coming from the Captain's side!"
"The Captain's in danger!"
"Hurry!"
Shinigami stationed at the Fifth Division were the first to be alarmed. Their expressions changed as they rushed toward the Captain's office.
When they reached the blast site, the scene that greeted them left them frozen in shock.
Amid the ruined rubble, Kaiser stood on the shattered floor, gripping Aizen's neck with one hand, lifting him into the air. His other hand held a Zanpakutō, thrusting forward.
"Shhk!"
The bloodstained blade pierced through Aizen's chest, entering from the front and exiting the back in a burst of blood.
"…"
Aizen's eyes widened, filled with shock, regret, pain, and disbelief as he looked at Kaiser.
"Why…"
He coughed blood and uttered that word, as if betrayed by someone he trusted.
"Captain!"
"Captain!"
The Shinigami of the Fifth Division screamed in rage.
"What are you doing?!"
Several of them charged at Kaiser in fury, blades swinging.
Kaiser didn't even glance at them. He simply looked coldly at the bleeding Aizen and spoke.
"So that's your trick?"
Kaiser tossed Aizen's body aside like garbage and tightened his grip on the Zanpakutō.
The furious Shinigami swung at him, but it was like striking stone—their blades couldn't even break his skin.
Kaiser's Reiatsu was already overwhelming, no weaker than Kenpachi Zaraki's—perhaps stronger. Just as Kenpachi could use his Reiatsu to make his body nearly invulnerable, Kaiser could do the same.
To wound him, one would need at least a Lieutenant-level opponent.
Even Renji Abarai, an elite among Lieutenants, could have his blade stopped with just a finger.
So damaging Kaiser required a Captain-level opponent—anything less was pointless.
Unfortunately, the Fifth Division didn't even have a Lieutenant at the moment. All that remained were ordinary Shinigami, and even those of Seated Officer level couldn't touch him.
Still, they showed no fear and instead roared at Kaiser in anger.
"Why did you kill Captain Aizen?!"
"Have you lost your mind?!"
"Answer us! Captain Kaiser!"
Every Shinigami who had come shouted accusations at him.
Despite knowing he was a Captain, they didn't hesitate. They were consumed with rage.
It showed just how deeply Aizen's image had been ingrained in the Fifth Division.
They could never know—that image was fabricated.
Including everything they were seeing now—it was all an illusion.
Kaiser could clearly sense it: a familiar feeling of being watched, and that strange sense of wrongness, was fading.
"…Escaped, huh?"
Ignoring the shouting and accusations around him, Kaiser clicked his tongue.
More Shinigami were arriving. Their faces changed at the sight.
The place was becoming more and more crowded.
Crowded to the point it chilled the heart.