In the name of teaching the way of swordsmanship, he executes a calculated trial.
As a Gotei 13 captain, it becomes an act of oppression disguised as education.
Rank, authority, and a justified pretext are all in place. Even if consequences arise later, it can be rationalized and walked back.
Akira immediately understood when Hirako Shinji drew his Zanpakutō and thrust forward—
This wasn't an instructional spar. This was a lethal strike aimed at killing Aizen.
At this point in time, Aizen was merely a first-year student, freshly enrolled in the Shin'ō Academy for only three days. He wasn't the manipulative king who, a century later, would wield Kyōka Suigetsu to deceive the Gotei 13 and defect from Soul Society with the Hōgyoku in hand.
Not even close.
Even when Aizen eventually graduated and became the Fifth Division's lieutenant, he wouldn't yet be invincible—
But he'd already reached heights in Zanjutsu, Hohō, Kidō, and Hakuda that placed him above most seated officers.
Back then, his Reiatsu, Zanpakutō mastery, and intellectual prowess were enough to earn Gotei-level scrutiny. If not, he wouldn't have been granted access to study the Hōgyoku in secret.
But now?
He hadn't even touched upon the four fundamental Shinigami arts.
He had only begun training in Kidō just two days prior.
He hadn't received any instruction in Hakuda.
Shunpo and Zanjutsu? Not even a single class yet.
In a direct clash against a captain like Hirako Shinji—
Victory was technically possible, even total domination—
But only if Aizen unleashed everything, exposing the full hypnosis of Kyōka Suigetsu in front of dozens of witnesses.
"Is Shinji doubting Aizen the man, or doubting the Zanpakutō?"
"Or is he trying to expose both?"
"A Zanpakutō that sees into the soul… sees the wielder's soul as well."
Thoughts exploded in Akira's mind as he analyzed the unfolding scene.
As expected—
Under the barrage of Hirako Shinji's vicious, merciless swordsmanship, Aizen—who had never once trained in formal kendo—was immediately overwhelmed.
Forced to retreat step after step.
Had their Reiatsu not been nearly equal—an anomaly in itself—any other freshman would've been cut down within the first exchange. Even the top-ranked students in the elite first class would have suffered serious injuries just facing Shinji's blade.
Watching everything with sharp clarity, Akira slowly extended his right hand toward the hilt of his Zanpakutō—
And then stopped halfway.
Because amidst the dazzling flurry of Shinji's sword, which resembled a storm of falling plum blossoms, Aizen turned his head subtly and shot him a look.
Don't intervene.
A signal as clear as if spoken aloud—he would endure this. He could handle it without revealing Kyōka Suigetsu.
"He still wants to conceal his abilities?"
"Still refuses to unsheathe Kyōka Suigetsu?"
"Is he too talented… or just too proud?"
"Does he really think this is about sword instruction?"
Hirako Shinji narrowed his eyes.
He could feel it.
The boy in front of him was absorbing every stroke of his kendo with terrifying speed, evolving in real time.
Every movement, every parry, every shift of footwork—Aizen was dissecting it all, internalizing it with frightening precision.
This won't last much longer, Shinji thought, a rare flicker of awe appearing in his sharp gaze.
If Akira continues to improve like this, then defeating Aizen—even with superior swordsmanship—will soon become impossible.
After all, the boy possessed Reiatsu on par with a captain.
Snap.
With that thought, Shinji raised his left hand and transitioned from single-handed to double-handed grip.
Bright yellow spiritual pressure burst from him in waves, expanding outward in visible ripples, flooding the Mao Kendo Dōjō with overwhelming pressure.
Clang!
As their blades collided again, Aizen felt crushing force travel down his Zanpakutō. It wasn't just weight—it was momentum, relentless and layered with intent, forcing him backward repeatedly.
At the same time—
Hirako Shinji lifted his sword above his head, then cleaved through the air.
Boom!
A concentrated blast of Reiatsu exploded forward, transforming into a massive, visible energy slash—
A compressed arc of spiritual power that howled through the dojo, distorting the air itself—
It raced toward Aizen like a falling star, a meteor of golden light with killing intent engraved into its form.
"Aizen!"
Several students cried out at once, springing to their feet.
By now, even the slowest among them realized—
This was no training match.
This was a real battle. A battle with lethal consequences.
One meant to kill Aizen.
And under ordinary circumstances, facing a captain-level Shinigami's full-power sword technique—
One that combined both Reiatsu and kendo mastery—
Even Tousen Kaname and Komamura Sajin, who also only recently began Shinigami training, would be powerless.
Even Shihōin Yoruichi, Shiba Kaien, and other noble-born prodigies, raised from birth to inherit the Shinigami way, would be overwhelmed in this moment.
Bakudō #81: Danku—Splitting Void."
Just as the Reiatsu-infused slash shot forth, about to engulf Aizen completely, a calm voice—devoid of emotion—cut through the chaos.
It wasn't loud.
Yet in the storm of spiritual pressure, confused gasps, and distorted energy waves flooding the Mao Kendo Dōjō, the voice carried clearly to every single ear.
Even Hirako Shinji heard it.
Boom!
In front of Aizen, a translucent barrier surged upward from the floor—
Like a wall of spiritual crystal, it rose with commanding presence, immovable and impervious, like a mountain forged of divine Reiatsu.
The moment the slash collided with the wall, the impact resounded throughout the dojo.
Reiatsu surged and splintered—then dissipated.
The defensive wall of Danku remained entirely intact, completely unscathed. Not even a ripple on its surface.
"W-What…?"
"That's… Bakudō #81! Danku!"
"It blocked a full-powered Reiatsu slash… without even a chant?"
"He's only been practicing Kidō for three days!"
Eyes across the dojo turned toward the caster.
Shihōin Yoruichi, Shiba Kaien, Byakuya Kuchiki—all turned their heads sharply, their expressions frozen in disbelief as they stared at Akira, still seated cross-legged by the wall.
"That's the highest-level defensive Bakudō short of forbidden spells…"
"Even I couldn't pull it off with such stability," Yoruichi murmured, eyes narrowing.
"Casting Danku without incantation…?" murmured Byakuya, his aristocratic composure momentarily shaken.
"…He may be more terrifying than Aizen."
Even Hirako Shinji, who had already seen Aizen's uncanny swordsmanship growth earlier, couldn't hide his astonishment.
If Aizen's adaptability in battle had been impressive, then Akira's instant chantless casting of Danku—the highest defensive Bakudō—was something else entirely.
Shinji had lived over two centuries.
He had seen prodigies.
But never someone who could discard an incantation and cast Bakudō #81 flawlessly after merely three days of exposure to Kidō.
"This is absurd," Shinji muttered to himself.
Akira met his gaze.
His tone was neutral, bordering on cold:
"That was excessive, Captain Hirako."
"Huh? I'm just conducting class," Shinji replied with a smirk, tilting his head with exaggerated innocence. "What're you talking about, student?"
"I don't quite follow either," Akira answered, voice still even.
"But from my perspective, you've taken unilateral action and disrupted class order."
"That's difficult for me to justify."
Shinji scratched his cheek, his grin unfazed. "Oh? Is that right? My bad!"
"But since I've impacted Mr. Shinji's class, then it's only right I take responsibility," Akira said as he slowly stood, brushing nonexistent dust from his robes.
"My younger brother's talent is… developing. His strength is limited. Forcing him to play assistant in a swordsmanship demonstration is both unfair and detrimental to the lesson."
He stepped forward, steady and poised.
"How about this—I'll take his place."
"I'll serve as your assistant, Mr. Shinji."
Though his words were phrased as a question, his body and presence gave no room for refusal.
Akira's tone didn't shift. He wasn't seeking permission.
He was declaring it.
"…Alright then."
After witnessing a no-chant Danku that withstood captain-class spiritual pressure, Hirako Shinji found himself just as curious as he was cautious.
Whether Akira was another Aizen—dangerous, deceptive, and long-planned—or a true genius born under the heavens, this was the best time to probe deeper.
If he turned out to be the latter, Shinji didn't mind. He respected true talent. He wouldn't resent it.
But if it was the former—if Akira, like Aizen, wore a mask and held deeper motives—then now was the time to uncover the truth.
Because the next time they clashed… it might be as enemies.
And in that future, knowing who the other truly was could mean the difference between life and death.