At this moment, countless Shinigami within the Gotei 13 felt the surge of a towering Reiatsu.
"This Reiatsu..."
"It's from that one in Division 3!"
"It's Captain Kaiser!"
Many Shinigami who had sensed Kaiser's Reiatsu up close before immediately recognized its owner, causing a stir among them.
Especially Rukia, who was still within the Division 6 barracks—she had been left bewildered by the sudden disappearance of Kaiser and her brother. The moment she felt Kaiser's Reiatsu, she looked in that direction at once.
"So this is Captain Kaiser's Reiatsu...?"
Even though the distance wasn't near, Rukia felt as though a monstrous floodbeast had appeared before her, roaring toward her. She couldn't help but wrap her arms around herself.
"Why would Captain Kaiser be releasing such intense Reiatsu?"
"Is he fighting?"
"Against... Brother?"
Rukia's expression changed several times in just a few seconds.
She wanted to rush over and stop the battle, but she found that her legs wouldn't move at all. They kept trembling, and she couldn't step forward.
It wasn't just Rukia—many of the Shinigami who felt Kaiser's Reiatsu experienced the same. Though they wanted to go investigate, their instincts kept them frozen in place, warning them not to approach.
Kaiser's fully unleashed Reiatsu would exert pressure even on Captain-class Shinigami. For those far below that level, it was unbearable.
So, they didn't dare get near that sky-piercing Reiatsu. Only a select few—like Kenpachi Zaraki—were not only undeterred, but drawn to it as if provoked, and approached the source.
As for Byakuya Kuchiki, who was directly facing the Reiatsu, he seemed to be caught in a storm. His pupils shrank to the size of a needle tip, and a trace of shock surfaced on his face.
"This Reiatsu..."
Sensing Kaiser's full-power Reiatsu at such close range, Byakuya was stunned. He didn't even care that Senbonzakura's blades were being scattered by the pressure, only staring in a daze at Kaiser, who was radiating golden Reiatsu.
Bathed in golden Reiatsu, Kaiser slowly raised the Zanpakutō in his hand.
"Haa!"
With a powerful slash, golden Reiatsu flew out from the blade, forming a sword pressure like a golden flood. It surged forward, barreling straight toward Byakuya.
Wherever the golden sword pressure passed, the ground was torn apart. The floating cherry blossoms were shredded, and even the cherry trees were uprooted. The once-beautiful landscape now lay in ruin.
"Proud child of Heaven, ironclad citadel, dragon stride—lion's roar—tiger's howl—wolf's rush—cut off the world before collapse!"
Without a second thought, Byakuya stretched out both hands and loudly chanted a Kidō spell.
"Bakudō #81: Dankū!"
A transparent barrier instantly rose up, standing tall in front of him, blocking the oncoming golden sword pressure.
"BOOM!!!"
The golden sword pressure crashed into the transparent barrier, triggering a thunderous explosion.
At once, fierce winds stirred, mixed with golden Reiatsu rolling through the air.
Reishi was scorched, the earth was ruined, and the golden sword pressure ground everything it touched to dust—immense and terrifying.
"Crack! Crack! Crack..."
Under the impact of the golden pressure, the transparent barrier began to waver. Cracks appeared on its surface, and Byakuya's expression changed again and again.
"Even Dankū is...!?"
He didn't want to believe his own eyes.
The spell said to perfectly block Hadō below #90, Dankū, now showed signs of collapse under the pressure of the golden sword wave.
"Senbonzakura!"
Byakuya gestured, and a mass of cherry blossom petals flew in, gathering at the hilt he held. They reformed into the blade of his Zanpakutō.
He swung the Zanpakutō, apparently intending to use sword pressure to counter the golden surge that was crashing into his barrier.
"Whoosh!"
However, without any warning, a figure suddenly appeared behind him. Without hesitation, he turned and slashed backward.
"Clang!"
In a crisp clash of blades, a Zanpakutō appeared like a ghost and struck, colliding with Byakuya's.
"Slash!"
Just as Byakuya thought he had parried the strike, he suddenly found that the blade had disappeared—only to strike his side, carving open a deep wound.
"Clang!"
"Slash!"
Ignoring the wound on his side, Byakuya turned his blade to meet another sudden strike from the opposite direction, only for that Zanpakutō to twist upon impact, flashing sparks as it reversed and cut open a gash in his thigh.
"So fast...!"
Byakuya staggered back several steps as if struck by lightning, his handsome face paling.
Watching Kaiser, who appeared before him cloaked in golden Reiatsu and lifting his blade once more, Byakuya raised a finger.
"Bakudō #61: Rikujōkōrō!"
Six flat, uniform beams of light flew in from all sides, aiming to pin Kaiser's waist.
But just before they touched him, Kaiser's Reiatsu exploded again—instantly shattering the six beams.
"Bakudō #61: Rikujōkōrō."
Then, Kaiser also raised a finger, casting the same Bakudō. Six beams shot from all sides, pinning Byakuya in place.
"Damn...!"
Feeling himself immobilized, Byakuya's expression instantly changed.
"Whoosh!"
Kaiser stepped forward with Shunpo and arrived before him in an instant.
"Slash!"
His resplendent Zanpakutō hacked down violently, sinking into Byakuya from the shoulder all the way through.
"———"
Byakuya's eyes widened, his expression frozen. The Reiatsu around him visibly weakened at a rapid rate.
It looked unmistakably like a dying man.
Unfortunately...
"Who are you trying to fool?"
With a flick of his Zanpakutō, Kaiser revealed that the frozen Byakuya had vanished like an illusion, leaving behind only a white, sleeveless Haori—sliced cleanly in two by the blade.
Kaiser turned to look behind him.
There stood Byakuya, now without his Captain's Haori, panting lightly and staring at Kaiser as if looking at a monster.
"Secret Shihō Step, Utsusemi."
Kaiser said plainly.
"By accelerating with Shunpo and leaving behind a discarded outer robe, you fool the enemy into thinking they struck your real body when it was only your clothes. Not bad—pretty practical."
His words made Byakuya's expression quite unpleasant.
He didn't particularly like using this technique.
Because it was something he learned as a child from someone he disliked.
That person had since betrayed Soul Society, making Byakuya loathe him even more.
Thus, Byakuya rarely used it—because it reminded him of that detestable man.
"So this is your true strength?" Byakuya muttered. "No wonder you and that brute were both made Captains without even knowing Bankai."
"Just that overwhelming Reiatsu alone is enough for Captain-level power."
"With this power equivalent to a Bankai, it doesn't matter whether you have one or not—that must be what Captain Commander Yamamoto thinks."
To Byakuya's assessment, Kaiser gave no comment.
Indeed, it was because Kaiser had Captain-level power that Genryūsai Shigekuni Yamamoto ignored the unspoken rule that Captains must master Bankai and appointed him as Division 3's Captain.
But beyond that, Yamamoto was likely also hoping—hoping that this overly young genius might reveal even greater possibilities in the future.
After all, unlike the monstrous Kenpachi Zaraki, Kaiser had only just become a Shinigami—and yet within days of receiving his Asauchi, he had already achieved Shikai.
A person like that—who would dare say he'd never attain Bankai?
Yamamoto believed that something like Bankai would not trouble Kaiser at all.
And when he eventually reached it, he'd become even stronger—perhaps even one of the most powerful among the thirteen Captains, rivaling Yamamoto himself.
Byakuya hadn't thought of this—nor had most Captains. They merely assumed Kaiser had no Bankai and lumped him together with Kenpachi, assuming they were both exceptions incapable of Bankai.
Only Yamamoto and a few sharp-minded individuals had connected the dots—and either trembled or anticipated what Kaiser's future might hold.
Of course, not even Yamamoto would have guessed that Kaiser had already mastered Bankai—and had done so at the exact same moment as Shikai, the instant he first touched an Asauchi.
If Yamamoto knew, even he might not remain composed.
But Kaiser had no intention of publicizing this.
He merely looked at Byakuya and said:
"So this is the tip of the iceberg of that power I'll never understand? Doesn't seem like much to me."
That line ignited the fire in Byakuya's chest.
"...I admit, I underestimated you."
Byakuya took a deep breath, tightening his grip on his Zanpakutō.
Originally, he had only meant to teach Kaiser a lesson—a warning. He hadn't planned to take things this far.
But now, holding back was no longer an option.
"Very well. Let me show you the true form of this power."
Byakuya raised his Zanpakutō again.
Only this time, he didn't lift it upright—instead, he lowered it, holding the blade upside-down.
"Burn this moment into your eyes and your soul. Remember it forever."
"Remember this power—written into Soul Society's very history, possessed only by those who stand at its pinnacle."
"This is the true final form of a Zanpakutō."
Byakuya intoned softly.
"Bankai..."