After the initial excitement faded, Aizen found himself contemplating a more pressing concern—Masatsuki Aozaki.
With his overwhelming talent and intelligence potentially on par with Aizen's own, he could become an even greater threat in the future than Shigekuni Yamamoto.
But a collapsed secret chamber wasn't enough to prove that Masatsuki had actually developed anything.
It was just as likely that he had destroyed the site to prevent his research from being discovered.
After all, being the Captain-Commander's disciple made him a particularly sensitive figure, and Yamamoto himself was an infamously stubborn man.
Besides, Masatsuki wasn't someone Aizen could move against lightly.
Thinking about the people gathered around him, Aizen felt an impending headache.
None of them were easy to deal with.
Yamamoto's strength needed no explanation. As his disciple, if Masatsuki were to be harmed, an investigation would be inevitable—potentially undoing years of careful planning.
Kirio Hikifune and Kisuke Urahara were formidable in their own right, with Urahara in particular being an intellectual rival, perhaps even surpassing Aizen himself.
And to make matters worse, Kirio was accompanied by a Zero Division member.
With reiatsu that exceeded that of a standard Shinigami, his Kyōka Suigetsu ability would be useless. Even his decoy had to avoid the 12th Division's territory altogether.
This was turning into a real nuisance.
Was this all part of your plan, Masatsuki-kun?
You truly are a man whose intelligence rivals mine—you've thought everything through, haven't you?
If Masatsuki knew what Aizen was thinking, he would probably tell him he was overanalyzing things.
Masatsuki had every reason to be confident.
Not only was he surrounded by capable allies, but he also understood exactly the kind of man Aizen was.
However, he was self-aware enough to recognize his limits. His intellect was merely above average—in a battle of wits, he wouldn't win.
His success with the Hōgyoku had only been possible thanks to the technical expertise of Kirio Hikifune, Kisuke Urahara, and Mayuri Kurotsuchi.
Compared to those three, he was nothing more than a skilled amateur.
...
Beneath the moonlight, Aizen gazed at his reflection in the water. He pursed his lips before allowing a faint smile to form.
He knew that the reasoning he had just laid out—his supposed logic—was both factual and an excuse.
Because deep down, he didn't want to kill Masatsuki Aozaki.
If anything, he wanted to see just how far he could grow.
"...I'll wait until the Zero Division returns to the Soul King Palace before making any decisions," Aizen murmured as he stepped to the shore of the lake, his narrowed eyes scanning the silent forest.
"Masatsuki… let's see who will be the one standing at the end."
...
Tōsen Kaname, who had been silently awaiting orders, suddenly stiffened. "What?"
"Nothing. We still don't know how far Masatsuki-kun has progressed." Aizen turned back slightly, casting a glance at Tōsen's serious expression. "I want more information. Take some men and investigate."
Tōsen hesitated. "Do you really think he could complete something that even you weren't able to create?"
"Of course not. That research isn't so easily replicated," Aizen replied, shaking his head. "Just gathering the necessary materials would be an immense challenge, not to mention the technical expertise required. None of those details were included in the data I gave him."
For a brief moment, disappointment flashed across Aizen's face.
Even you can't understand me, Tōsen?
You really are far beneath that man.
"What? Do you still have doubts?" Aizen didn't turn around, his gaze remaining fixed on his own reflection in the water.
"No, I just want to know where to start. Should I confront Masatsuki Aozaki directly, or investigate the people around him first?" Kaname Tōsen frowned slightly.
If Masatsuki was as clever as Aizen suspected, neither approach would yield much useful information.
"Oh? Let's start with this basement then. See if you can find any clues."
Aizen finally turned around, letting out a sigh as he gave the order.
...
In the dead of night, the Kagarashi District of East Rukongai was silent. Two young men exchanged peculiar looks.
Though blind, Tōsen's other senses were exceptionally sharp—he could feel Aizen's piercing gaze on him.
Tōsen wasn't a fool. On the contrary, he was a strategist, skilled in warfare and deception. That's why he immediately realized he had made a mistake.
If Masatsuki couldn't be touched before the Zero Division left, then the best course of action was to start somewhere less significant.
And this abandoned basement was the perfect place to begin.
Inwardly, he marveled at Aizen's insight—how effortlessly he saw through everything.
...
11th Division, Captain's Quarters
As the 3rd Seat, Mashiro Kuna had taken it upon herself to clean the Captain's quarters.
After a quick fifteen-minute tidying session, she was already finished.
Meanwhile, Masatsuki Aozaki sat cross-legged on his bed, his Zanpakutō resting on his lap as he focused on Jinzen meditation.
To achieve Bankai, one needed complete understanding of their Zanpakutō. Banshō had carefully structured his training schedule down to the second—Masatsuki had no intention of wasting even a moment.
"Captain's exam?" He frowned as he listened to Mashiro's explanation. The term felt both familiar and foreign.
"That's right. At the next Captain's meeting, a candidate will be present. Supposedly, someone has mastered Bankai and has submitted a request for promotion," Mashiro nodded as she explained.
Masatsuki raised an eyebrow.
It must be the candidate for the 3rd Division captaincy—the only vacant position in the Gotei 13.
That seat had remained empty for a long time, with Chikane Iba serving as acting captain in the meantime.
In the original timeline, the position was eventually filled by Rōjūrō Ōtoribashi.
Masatsuki had looked into it—Ōtoribashi had indeed been training for Bankai, but he hadn't succeeded yet.
Had he recently broken through?
Or… could it be Kōga Kuchiki?
After the war, it made sense that a Shinigami with Bankai wouldn't remain in the Special Forces, but wasn't he just Ginrei Kuchiki's lapdog?
"In any case, you don't need to worry about it. The selection process has nothing to do with us—the candidate is just vying for the 3rd Division captaincy."
Having been a Shinigami for nearly a century, Mashiro was well-versed in these procedures. She waved a hand dismissively, radiating confidence.
"You just have to join the other captains and determine whether he's truly qualified for the position."
"Who's the candidate?"
Masatsuki prided himself on knowing this world inside and out, but things had already deviated from the original course. He needed confirmation.
"No idea. The candidate's identity hasn't been revealed yet," Mashiro said as she casually settled herself in his lap.
"I see… I wonder who it could be."
As his Banshō Senran training session concluded, Masatsuki set his Zanpakutō aside.
Still, he couldn't shake a strange feeling in his chest.
"You've been training for so long—you should take a break," Mashiro said approvingly as she eyed him. "You still smell fine, but you need a proper wash."
With that, she pointed toward the bathroom.
Masatsuki hesitated for a moment before finally getting up and heading inside.
...
Lying in the bath, he clenched his fist and exhaled slowly.
"Without realizing it… I've reached the point where I have a say in who becomes captain."
He thought back to when he had first arrived in Soul Society—back when he could barely find enough to eat.
And now… he had the power to influence the future of the Gotei 13.
...
(40 Chapters Ahead)
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