"That was in the past."
Aiyan didn't take Shiba Isshin's words seriously. The so-called record of taking ten years to achieve Bankai meant nothing to him.
No one understood better than Aiyan how proud his Zanpakutō was.
Now that it had declared it could achieve Bankai in three days and fully master it in half a month—when other Shinigami might need decades—there was no way it would fall behind. If anything, it would only exceed expectations.
"You've already reached the threshold of Bankai, haven't you?"
"Right," Shiba continued. "Once your Zanpakutō manifests and pulls you into your inner world to speak with you… if it even willingly submits, then mastering Bankai might not be far off!"
Judging by Aiyan's calm expression, Shiba couldn't help but suspect that this monstrous student had already reached the threshold of Bankai.
And somehow, it felt entirely reasonable.
"After 27 more days, we'll know for sure."
"By then, I'll have to ask you a favor, Teacher Isshin."
"I'll need 200 Shinigami to stand in as my audience."
Aiyan smiled faintly, not wanting to elaborate too much on the subject of Bankai.
The "threshold"? He didn't need to do anything.
His Zanpakutō, Kōfūin, would build the Bankai itself and hand it over to him when the time came.
Even Shiba Isshin, with all his imagination, could never guess the truth—that this young man didn't have to do a thing.
"Worried that Hirako might back out after he loses?" Isshin asked, sensing Aiyan's calm confidence.
For nearly all Shinigami, becoming a captain of the Gotei 13 was like standing before a massive, insurmountable mountain.
But the black-haired youth in front of him didn't seem fazed.
To Aiyan, it was just a checkpoint on the path to true power—a temporary pause before moving forward.
"What do you mean 'worried'? You were the one who said it, Teacher Isshin. In order to replace a captain, you must defeat one in front of 200 Shinigami."
"So of course, I'll need your help."
"You're the only one willing."
Aiyan chuckled.
But in his heart, he was sure Hirako Shinji wouldn't back down.
After all, Hirako was the type who, once he sensed danger—especially from someone like Aizen—would go all in.
He was a captain who knew how to push boundaries and use any means necessary.
There was nothing he wouldn't do.
"Don't make me hate myself."
"I can get you 200 Shinigami, but only if you promise me one thing."
"Don't kill Hirako Shinji. Let him live as long as possible."
Isshin's words stunned everyone nearby—Shihouin Yoruichi, Komamura Sajin, and the rest.
What did he mean?
Did he already assume Hirako Shinji would lose?
"Teacher Isshin, shouldn't you be saying that to Captain Hirako instead of me?"
Aiyan raised his hands as if in protest.
"Aiyan, please agree to this."
"I'm not asking this just for Hirako's sake. It's for yours too."
"Sure, killing a captain in a formal duel isn't illegal. But the Fifth Division isn't like the Eleventh. Soul Society can accept one Kenpachi, but not two."
"Hirako Shinji is a well-connected captain with influence. If you kill him, many other captains, lieutenants, or even the Captain-Commander will take issue with it."
"It would make things difficult for your future."
Isshin spoke seriously.
He knew Hirako was responsible for the situation, but he also knew he couldn't change Hirako's mind.
So he had no choice but to appeal to Aiyan.
"We'll see."
Aiyan didn't promise, but he didn't reject it either.
Isshin sighed.
That was good enough.
His connection to Hirako wasn't deep anyway.
He'd done all he could.
Once class ended, under the watchful gaze of Isshin, Yoruichi, and the others, Aiyan and Aizen 'left' the Kendo Hall, heading for the dormitory.
At least, that's what it looked like.
In reality, neither of them had moved an inch. They were still seated inside the Kendo Hall.
All of this was part of Aizen's illusion.
"We really caught a big fish."
"And not just one."
"There's a whole group tailing us."
Aiyan sat on the Kendo Hall steps, leaning back casually.
"Expected."
"Seireitei has stood for over a thousand years. Of course, there are people who can see through my disguise."
"Too bad, what they saw is exactly what I wanted them to see. What they fear is exactly what I want them to fear."
Aizen smiled.
At that moment, every teacher and student in the Spiritual Arts Academy was still under the illusion of Kyōka Suigetsu.
If anyone overheard their real conversation, it would shake the entire Soul Society.
Especially Hirako Shinji.
He believed he had spotted something dangerous, when in fact, every step he took was guided by someone else's hand.
"You're right," Aiyan said.
"Hirako is good at reading people—but not good enough. He can see you, but not me."
"He thinks he found us. But from the beginning, it was us who selected him."
"Since yesterday, I cast Kyōka Suigetsu across the entire academy, just to draw him in."
The weight of Aiyan's words was chilling.
Hirako Shinji hadn't stumbled upon them.
He was baited, lured—chosen.
"If he's going to become an obstacle, then we should just remove him, along with the other captains close to him."
"Of course," Aizen added, "as you said, even toilet paper and underwear have their uses. A captain should be useful too."
"You can take his division."
"I have other plans for him."
Aizen's voice was calm.
As if he were talking about a bug—not a captain of the Gotei 13.
"Experiments?" Aiyan guessed.
"Exactly."
"I've been combing through the Spiritual Arts Academy's archives, and I've spoken to both Isshin and Jūshirō Ukitake."
"Reiatsu enters a Limit after a certain point—growth slows to a crawl."
"Eventually, Shinigami hit a bottleneck that can last ten years… a hundred… even thousands."
"Not just Reiatsu—Zanpakutō, Kidō, Hakuda, Hohō, even Kendo—all reach a bottleneck."
Aizen's expression turned serious.
"Take Reiatsu, for example. Once it's ten times what I have now, I believe I'll reach my limit."
"Any growth afterward would be extremely slow."
"That limit… every Shinigami faces it. The only way to break it is through external force. It's likely the same for Hollows."
"Even with Bankai, where Reiatsu multiplies five to ten times—it eventually hits the ceiling again."
"It's meaningless."
He said this with frustration.
Frustration at being unable to chase higher power.
"Ah, that's the '60-Kensei' point."
Aiyan nodded casually.
He was curious—would he hit the same wall Aizen did when he reached that point?
"60… Kensei?"
Aizen blinked, confused.
He had studied everything in the Spiritual Arts Academy's library, but had never heard of this term.