"What about Brother Akira?"
"I couldn't be certain before," Yamada Seinosuke replied, his voice calm but edged with subtle reverence, "but judging from their clean sweep of the two Hunting God squads, your hypothesis was right, Lord Shitan. The Akira brothers do indeed carry fragments of the Spirit King within them—and not in insignificant amounts."
"Only such fragments can explain the grotesquely accelerated growth they've shown. Just one day of contact with Zanpakutō and Kidō, and they've already made breakthroughs equivalent to a seated officer's training over years."
Seinosuke adjusted his gloves, his expression unreadable.
"There will be other chances."
"For now, the fragments I possess are sufficient to prolong my experimentation. Let them live a little longer. Let them inhale a few more lungfuls of Soul Society's reishi-rich air."
"In a way, they've done me a favor—bringing those Spirit King fragments to my doorstep. It's only fair to offer a temporary reprieve."
Tsunayashiro Tokinada tapped his fingers against the armrest of his ornate chair, lost in thought.
In his mind, he'd already decided: the Akira brothers would leave the Spiritual Arts Academy before he acted again. Their presence had stirred too much attention. With Genryūsai Yamamoto and Jūshirō Ukitake already monitoring them, any further moves within the Academy would be risky.
There was no longer any hope of operating under the radar.
He would wait. Time was his weapon.
Once the old lions turned their eyes elsewhere, he would strike with finality.
The following day.
Akira and Aizen entered their classroom as if nothing had happened the previous night. No one suspected that they had crushed two entire assassination squads. Calm, quiet, and unreadable—they made no mention of it, not even in passing.
However, unlike yesterday's Kidō lecture, today's Zanpakutō class wasn't taught by Ukitake Jūshirō. Instead, a tall man with short black hair, a lean, slightly unshaven face, and a white haori with the 10th Division insignia stepped into the room.
"Yo! Good morning, everyone."
He kicked open the classroom door and used Shunpo to appear at the podium in a single flash. His tone was casual, his grin disarming.
"My name's Shiba Isshin. You can call me Teacher Isshin or Teacher Shiba."
"I'll be taking over for Jūshirō today to teach you the basics of communing with your Zanpakutō."
He glanced around the room, hands in his sleeves, as if expecting applause.
Silence.
Everyone stared.
"Is that really Shiba Isshin?"
Akira leaned back in the last row, watching the new instructor with visible interest. The man's spiritual pressure was hidden beneath layers of playfulness—but that didn't fool Akira. There was something deeper here. Someone capable of vanishing from the records of Soul Society, only to later reemerge in the human world as Kurosaki Ichigo's father… a man who'd wielded a Zanpakutō even after sacrificing his Shinigami powers.
"A man who could fall… and rise again. A ghost who cast no moonlit shadow."
In terms of danger, aside from Yamamoto Genryūsai himself, this man was perhaps the most unpredictable force in the Gotei 13.
"Hm?"
Aizen noticed the shift in Akira's expression, the subtle flicker of interest. He mentally filed away the name Shiba Isshin.
Another piece for the board.
He'd gather more information on this captain-level anomaly after class.
"Tch. That fool hasn't changed a bit."
In a far corner, Shihōin Yoruichi sighed, pinching her brow in exasperation.
Even if he had made it to captain of the 10th Division, Shiba Isshin was still the same over-eager idiot who used to chase hollows barefoot through Seireitei.
As the childhood friend of Shiba Kukaku, she knew Isshin well.
"Ahem."
"Alright class, let's get serious."
Isshin spun around and wrote two massive characters on the chalkboard, his white sleeve fluttering like a banner.
刀禅
(Tōzen – Sword Meditation)
His strokes were bold, clean, and filled with spiritual weight—like Crescent Moon Getsuga slicing the night sky. Just looking at them gave the students goosebumps.
"The path of Zanpakutō liberation is divided into two stages: Shikai and Bankai."
"No matter which one you're aiming for, the essence is the same—you must enter your inner world and form a bond with your Zanpakutō."
"Hear its name—that's Shikai."
"Defeat its manifested form—that's Bankai."
His voice carried the casual warmth of someone who had long mastered the art, but beneath it was the iron core of battlefield experience.
If Jūshirō Ukitake explained things like a gentle wave, then Shiba Isshin taught like a sudden storm.
Even students like Byakuya Kuchiki and Shihōin Yoruichi, heirs of the Four Noble Houses, leaned forward ever so slightly. They, too, recognized the value behind Isshin's simplicity.
"Teacher Isshin, how do we enter the inner world?" asked Komamura Sajin, raising a large, clawed hand.
Isshin turned to him with a grin.
"Ever heard this saying?"
'Sincerity leads to connection.'
"It's not about shouting louder. It's about being honest—with yourself, and with your sword."
Place your Zanpakutō in front of you, rest your palm gently against the blade, then channel your Reiatsu into it. Use the sealed state as your connection, and your Reiatsu as the guiding thread."
"This is the essence of Sword Zen—Tōzen."
As he spoke with rare seriousness, Shiba Isshin paced slowly in front of the class, eyes sharp. At his urging, Akira and the other students unsheathed their Zanpakutō and mimicked the stance he demonstrated.
But the results were… unimpressive.
Other than a few students from prominent noble families—like Kuchiki Byakuya and Shihōin Yoruichi—who had already achieved Shikai, most showed no progress. Tōsen Kaname, Komamura Sajin, and even Tenbē Embroidery Assistant sat still, frustrated, their blades inert in their hands.
"Don't be so eager, rookies," Isshin said, smirking as he crossed his arms.
"A Zanpakutō is an extension of a Shinigami's soul. Like any soul, it has a unique personality. You can't force it to appear. If your spirit isn't strong enough—or if your sword doesn't recognize you—it simply won't respond."
He jabbed a thumb at himself with a crooked grin. "Take my case. My Zanpakutō's got a nasty temper. I spent an entire day trying to communicate with it. I managed to get one foot into my inner world, and before I could lift the other, the damn thing kicked me right out!"
The class chuckled. The tension loosened slightly.
Hearing that even a captain-level Shinigami had once been humiliated by his own Zanpakutō reassured the students. Their frustration faded, replaced by quiet determination. After all, if even Shiba Isshin had needed a full day to establish contact, then their own struggles felt less like failure and more like part of the process.
"Impossible!"
Suddenly, Isshin let out a sharp, shocked cry. The sound echoed through the room like a blade being drawn.
Everyone flinched. Tōsen Kaname's hand trembled so violently that his Zanpakutō nearly slipped from his grip.
"What the hell, Isshin!?" Yoruichi snapped, startled. "I was just getting close to making contact!"
She scowled, her gold eyes narrowed, obviously annoyed. "I almost threw my Zanpakutō across the room!"
But Isshin didn't even respond. He stood frozen, jaw slack, eyes locked on something in the back row.
His stunned expression drew everyone's attention.
They turned—then gasped.
On Akira's shoulder, an enormous red-scaled dragon claw had manifested from thin air, resting with deliberate care as if marking its territory. The very air around it shimmered with dense, suffocating Reiryoku. The claw radiated raw power, a physical embodiment of something far beyond a mere sealed blade.
"C-concretization…?" Isshin stammered. "That's… the materialization of his Zanpakutō spirit…"
Shock rippled through the room like a wave.
Isshin blinked hard. "What the hell is this? I told them to learn Tōzen… and this guy's already got his Zanpakutō spirit out? Is he… training for Bankai!?"
Indeed, in the standard progression of a Shinigami, materializing the Zanpakutō spirit is the first and most difficult prerequisite for mastering Bankai. It usually only comes after years of trust and compatibility.
But Akira?
His Zanpakutō spirit didn't just appear—it manifested willingly, powerfully, protectively. Not as a creature resisting its user, but one already surrendered in loyalty.
"S-so wait…" one student whispered, paling.
"Isn't materialization the first step toward Bankai?"
"Does that mean Akira is… one step away from mastering it?"
"This… this is insane. He only got his Zanpakutō yesterday!"
"Captain Jūshirō said it takes ten years minimum—even prodigies like Renji Abarai and Hitsugaya Tōshirō needed years of combat experience. And this guy… is about to finish it in two days?!"
The murmuring turned into stunned silence.
In the corner of the room, even Shihōin Yoruichi and Urahara Kisuke—who had slipped in without drawing attention—exchanged a glance.
They said nothing, but both were visibly shaken.
Shiba Isshin slowly turned his gaze back to Akira, who sat calmly beneath the looming crimson claw. His eyes were closed, completely immersed in Sword Zen. His breathing was steady. Tranquil.
The sword had already answered.
And the dragon had awakened.