The warning bells rang loud through the Seireitei, the deep sound echoing between the white walls and reverberating along every stone-paved street.
Lieutenant Abarai Renji of the Sixth Division had been defeated by one of the ryoka.
The defeat of a Lieutenant was not something that could be taken lightly. The fall of a Lieutenant was not just an ordinary loss, but a direct affront to the pride and strength of the Gotei 13.
Renji was known for his iron determination and his bond with the Kuchiki Clan. If even he had been brought down by a mere ryoka, it could only mean the intruders possessed a dangerous level of power.
It was in this climate that the Captain-Commander Yamamoto summoned all the captains to the main hall of the First Division. The great hall filled with the presence of the greatest forces of the Soul Society — all the Captains of the Gotei 13.
Standing at the center, Yamamoto rested both hands on the staff that hid his own zanpakutō. His long beard and thick eyebrows shadowed his stern gaze, and the reiatsu that emanated from him was so heavy it alone was enough to keep the room in absolute silence.
When he finally spoke, his voice echoed firm, filling the entire hall.
"All captains gathered here. From this moment on, you all have full authorization to release your zanpakutō within the Seireitei."
The heavy words echoed like hammers. Authorizing the full release of zanpakutō inside the Seireitei itself was an order rarely given.
It meant the situation had crossed every acceptable line and was now considered a war.
The captains exchanged glances in silence.
The fight against the ryoka had entered its most critical phase.
[——]
Hours later, on the sacred eastern wall, the wind blew cold.
Keiji stood in a relaxed posture, one hand resting on the hilt of his zanpakutō, his idle gaze fixed on the horizon. His stance said that none of the Soul Society's problems concerned him, but the reiatsu leaking out was enough to keep any rank-and-file officer well away.
It was in that heavy silence that calm footsteps echoed behind him, different from the running of the other shinigami.
"Keiji-kun."
Aizen Sōsuke's gentle voice cut through the air like a breeze. The white Captain's haori fluttered lightly in the wind, and his glasses caught the faint light from the nearby torches while the gentle smile painted a face that hid any hint of concern.
Keiji raised an eyebrow without even moving from where he stood.
"Oh, Captain Aizen."
The Captain of the Fifth Division stopped a few meters away. With a simple gesture, he adjusted his glasses with two fingers, making the lenses flash for an instant and hide his eyes.
"It seems the chaos caused by the ryoka is greater than many expected."
Keiji let out a quiet sigh, his fingers drumming on the zanpakutō's hilt.
"After all, as long as there is individuality in people, there will always be someone who doesn't accept injustice."
Aizen tilted his head slightly, the soft smile never leaving his face.
"Is that what Keiji-kun thinks? That it is unjust?"
Keiji waved his free hand lazily.
"Just or unjust depends only on who is telling the story. Something like that doesn't interest me much."
"So, what is it that interests Keiji-kun?"
Aizen's voice carried an innocent curiosity.
Keiji glanced up at the Seireitei's sky for a moment, then brought his eyes back to the Captain.
"Not many things. One of them is a certain incident from a hundred years ago."
Aizen's gentle smile didn't change as he listened to Keiji.
"Captains of the Third, Fifth, Seventh, and Ninth Divisions. Lieutenants of the Eighth, Ninth, and Twelfth. Even the vice-chief of the Kidō Corps…"
Keiji listed them in a calm voice, reciting the names he'd learned from Shunsui and Ukitake.
"They were all victims of hollowfication. Aizen-san was the Fifth Division's lieutenant at the time, right? Isn't that quite the coincidence?"
Aizen adjusted his glasses with two fingers, the light reflecting off the lenses and hiding his eyes for an instant.
"Keiji-kun know about that? Or did you meet people who shouldn't be walking around the Soul Society anymore and learn something from them?"
Keiji tilted his head slightly.
"The scapegoat? I did actually run into that Urahara Kisuke once."
"So that's why Keiji-kun has always been suspicious?"
Aizen closed his eyes for a second, as if everything had fallen into place.
"From the start, even though I showed nothing but kindness, you never stopped keeping your distance. I'm curious. Why is that? Is Urahara Kisuke that convincing?"
Keiji scratched the back of his neck slowly as he answered.
"Sorry, but I can't trust kind people."
"Oh?"
Aizen raised an eyebrow, his smile widening a little.
"I remember a line I heard back when I was alive…"
Keiji looked toward the horizon, as if he weren't speaking only to Aizen.
"'If the truth is cruel, then lies must be kind. That's why kindness is a lie.'"
He let the line hang in the air and then finished.
"Shinigami don't exist to be 'good'. We're all killing machines greased to keep the world in balance. Some can be naive, like Yamada-kun in my division, but those are the weak ones."
His eyes narrowed, studying every detail on Aizen's face. The Captain stayed calm, without changing that soft smile that seemed permanently attached to his face, like it was impossible to pull any other expression out of him.
"The captains… they're all monsters. They wouldn't reach that level if they weren't."
Keiji's words sounded simple, but they were loaded with conviction.
No captain reaches that post through kindness or gentleness. Raw strength, strategic intellect, and veiled cruelty are essential tools they all possess.
That's why he didn't trust any facade of kindness coming from them.
Captains like Zaraki Kenpachi, Kurotsuchi Mayuri, and Ichimaru Gin... even if they could hide their intentions, they were openly sinister.
On the other hand, someone like Aizen Sōsuke, Unohana Retsu, Kyōraku Shunsui… each of them wore a mask. Each hid something behind the image they projected. Shunsui hid behind his floral haori and lazy jokes; Unohana hid behind her gentle, maternal posture; and Aizen, who wore a smile gentler than a calm moon.
All of them were monsters.
Keiji, however, trusted kindness less than any other mask.
But his intuition said Unohana's kindness hid a "monster", not a "manipulator".
That fit him more, Aizen Sōsuke.
"I hadn't foreseen something like this."
Aizen finally spoke, breaking the silence. His voice was soft like a drizzle that seemed to slide by unhurriedly.
"What a splendid way to be found out. You really are a genius, Keiji-kun."
Keiji let out a dry laugh, almost mocking the praise.
Aizen adjusted his glasses, the lenses flashing in the Seireitei's light.
"Is that why you waited for me here alone?"
Keiji straightened up, facing the Captain of the Fifth Division head-on, without a hint of hesitation.
"I've got a few complaints with you, so I came to settle them."
"Complaints?"
Aizen drew the word out like it was music on his lips.
"A mere spectator thought he could use me for his own benefit. Isn't that a bit much?"
The look in Keiji's eyes showed absolute contempt for Aizen in that moment. His eyes didn't even seem to recognize the Captain of the Fifth Division as a "person".
Aizen sighed softly, though the smile never left his face.
"It seems Keiji-kun wasn't very pleased with some of the tasks he received. But is it really fine to talk to me like this? I'm still a Captain, after all."
Keiji answered with a crooked smile.
"Captain or not, that doesn't make any difference to me."
Aizen's smile widened a little, without losing its gentleness.
"Is this the confidence a genius ought to have? Splendid. But, if you'll allow me… even the fact that you're confronting me here, at this exact moment… was part of my plan, Keiji-kun."
The words echoed along the stone of the wall, carrying a calm that sounded threatening.
Keiji tilted his head slightly, looking at Aizen.
"Confidence? Plans? I'm not interested in your nonsense, Aizen-san. Do me a favor… lower your head and crawl back into the hole you've been hiding in for the last hundred years along with your 'plans'."
The two just stared at each other for a moment. Then the silence between Keiji's and Aizen's words suddenly broke with a crisp crack, followed by the sharp sound of steel clashing against steel.
In the blink of an eye, both figures vanished with shunpo, reappearing and disappearing every instant, like shadows cutting through space.
Their blades scored the air with absurd speed, throwing off silver sparks that lit the wall with every collision.
The weight of each impact made the stone floor shudder, cracks spreading like webs beneath their feet.
Aizen kept that gentle smile untouched, even as he blocked every fierce strike from Keiji. His movements were elegant, as if he were merely testing his opponent's limits in a spar. Keiji, on the other hand, attacked with raw power fused with technique, his eyes half-lidded and his body far too relaxed for someone in a fight.
In an instant, Aizen lifted his free hand, his fingers shining with reiryoku.
"Bakudō #61, Rikujōkōrō."
Six golden beams shot up around Keiji, compressing the space and locking his movements as if they were bars made of pure light.
But before they could restrain him completely, Keiji's body erupted with overwhelming reiatsu. The sound cracked the air like thunder. The columns shattered before touching his body, dissolved by the sheer pressure. The ground vibrated, chunks of stone rose up and crumbled, and the entire wall seemed to tremble.
It was the full reveal of a Level 2 Spiritual-Class reiatsu.
The wave spread across the Seireitei like a devastating tide.
Low-ranking shinigami dropped to their knees or fainted on the spot, unable to breathe. Seated officers stumbled, sweating and gritting their teeth just to stay upright. Only a few lieutenants managed to endure, even then with difficulty, as if heavy chains were clamped to their bodies.
Aizen narrowed his eyes for the first time, slowly adjusting his glasses as he watched his Bakudō get destroyed.
"That wasn't in my calculations. Keiji-kun reached that level in so little time?"
"'Little time'? It's been almost a decade. It would be shameful if I were weaker than this."
Keiji raised his right hand, his reiryoku gathering around it like crackling sparks of thunder.
"Hadō #63, Raikōhō."
The spell exploded in a golden flash, a beam of pure destruction that roared toward Aizen like a storm. The Captain dodged at high speed, the flash tearing through the wall behind him and reducing part of the structure to smoking rubble.
In the same instant, Keiji appeared in front of him with his zanpakutō in hand, striking without hesitation.
The blades clashed again at high frequency. Each blow rang like metal bells, reverberating between the walls.
Their movements were so fast they were barely trackable, only flashes of steel and bursts of reiatsu.
At the base of the wall, a group of shinigami were struggling to reach the top. Among them were the lieutenants of the Third, Fifth, Seventh, Ninth, and Tenth Divisions. Every step was a battle against the crushing reiatsu that dominated the field.
When they finally managed to climb up, what they saw made them freeze in place.
Up above, the two had stopped for a moment. The silence was cut by one last flash, and then the metallic ringing ended.
Keiji's zanpakutō was piercing straight through Aizen's chest.
The Captain of the Fifth Division widened his eyes and spat blood. His glasses fell and shattered on the stone floor.
His lips moved, as if he still had something to say… but no words would come out.
The gentle smile broke for the first time.
Keiji's blade slid out in a slow motion, and Aizen toppled backward, blood spreading across the white wall-top, staining the immaculate stones with a deep red that seemed to gleam under the pale sky of the Seireitei.
For an instant, there was no sound at all besides the slicing wind. Then a desperate voice echoed.
"Captain Aizen!"
Hinamori Momo was the first to scream. The shock cut across her face like an invisible blade, her eyes wide and her breath caught.
Her cry was the trigger that made all the lieutenants present react at once.
Their hands moved on instinct to the hilts of their zanpakutō, and the sound of blades being drawn filled the air.
The glow of Shikai flared one after another, each one revealing its unique form.
The rampart lit up in different shades of reiatsu — each lieutenant unleashing their own, like a chorus of unified fury.
All that hostility was hurled straight at Keiji. The lieutenants' reiatsu rose like invisible walls, choking the air around them. Even injured by his spiritual pressure from minutes earlier, they ignored the pain.
Keiji only let out a long sigh, bringing one hand to the back of his neck like an annoyed teenager.
"Yare yare."
His eyes calmly swept over each of the lieutenants, sizing them up as lesser opponents.
And so, by the end of that day, the news had spread throughout the Seireitei.
The Captain of the Fifth Division, Aizen Sōsuke, had been killed.