Chapter 273: Research Progress: Stalled
As it turned out, Matsushita Yusuke's plan was not going to work in the short term.
He didn't dwell on it for long. He knew himself well enough to understand that deep independent research was not his strong suit.
So he went to find backup instead.
"So. Something troubling you today?"
Aizen smiled pleasantly and poured Matsushita Yusuke a cup of hot tea.
"..."
He murmured a thanks and took a small sip.
Showing up at another captain's quarters in the middle of the day was not the kind of thing a normal person did. Captain-level figures needed reasons to visit each other, as had come up before. Without one, Yamamoto would be following up afterward with pointed questions. That was the kind of headache that was worth avoiding.
So Matsushita Yusuke had timed his arrival to the evening, slipping in with the particular energy of someone who was absolutely not doing anything suspicious.
Fortunately, Aizen's hospitality hadn't changed. They were both members of the Club, and the foundation between them was real.
Watching Aizen settle comfortably into his seat, Matsushita Yusuke scratched his cheek and spoke in a slightly halting tone.
"It's not exactly a problem. I've just run into some difficulty on the training side of things."
"Oh?"
Aizen's interest visibly sharpened.
He leaned forward slightly, a small smile at the corner of his mouth, and said with a faint teasing quality:
"A training problem that's actually giving Matsushita-kun trouble. Honestly, I don't think I'd have an answer for something like that."
Matsushita Yusuke stared at him.
So Aizen really did just say whatever he felt like.
He was briefly at a complete loss for words, which was not a state he reached often. After a short silence, Aizen smiled and spoke first.
"That was a joke. Please don't take it to heart. So -- what's actually going on?"
Matsushita Yusuke thought for a moment, then laid out the situation plainly.
"Aizen-sensei, on the subject of merging different types of power -- do you have any specific theories or frameworks you've developed around that?"
Aizen's eyebrow rose.
If his expression had been carrying casual ease a moment before, that quality was gone now. He had adjusted, and what had replaced it was something considerably more engaged.
"Now this is an interesting theory. Matsushita." A beat. "How did you arrive at this line of thinking?"
The reaction made complete sense.
Aizen had been working toward breaking past his own limits for years, exploring every avenue available. Hearing Matsushita Yusuke raise this specific question was, in its own way, exactly what he had been hoping someone would eventually bring him.
His pleasure was not concealed.
Matsushita Yusuke gave a brief, managed response and used the time to think through the angle he was working.
Aizen had eventually broken through using the Hogyoku's power. But before that, he had certainly done his own research and built his own theoretical foundation. The underlying logic and reasoning he had developed along the way was potentially the most useful reference material available.
As the person currently attempting this from the practical side, Matsushita Yusuke had no intention of skipping that.
"You want to know what I think about this? I see." Aizen considered for a moment, then stood and extended an invitation. "Matsushita-kun, if you have time, would you come with me?"
There was no real room to decline. Matsushita Yusuke accepted readily.
They left Squad 5's compound and made their way toward a research installation Aizen had set up at a separate location some years back.
These facilities represented accumulated infrastructure -- things built up gradually over time as the operation grew.
In the early days, Aizen had simply used the Research and Development Bureau's equipment directly, commandeering institutional resources without much concern. As time passed and the volume of work expanded, that stopped being practical. The appetite of all three of them had grown alongside their work.
To handle the increasing complexity, Aizen had identified locations throughout Soul Society that were difficult to notice and established them as research and transit points. The lack of dedicated maintenance meant the appearance was dated, but that was entirely expected. They were still operating inside the Gotei 13's administrative boundaries.
Jumping around under Yamamoto's nose like this was, in a certain sense, an expression of remarkable confidence in one's own continued survival.
Matsushita Yusuke followed him down into the underground level, turning things over in his mind as they walked, and then said with the air of someone landing on an answer:
"This would be the Western Laboratory -- the one that was open for a stretch a few years back?"
"Impressive that you still remember."
Matsushita Yusuke responded to the comment with a quiet smile. He raised his hand and ran it along the side of a dust-covered instrument panel, and something passed through his expression that was genuinely reflective.
"We built all of this ourselves, the three of us. If even we forgot it -- there wouldn't be anyone else left to remember it."
Aizen Sosuke went unusually quiet.
He moved through the space slowly, touching the instruments lightly, his wide lenses catching the dim blue light in the room and making his expression unreadable.
"That's right. This is the road we walked together. And only the three of us know it."
Going back to the beginning of the Club's existence, the full span from its founding to the present was roughly a hundred years. But the range of what the three of them had worked through together, the complexity of the obstacles they had navigated -- even looking back on it now, the weight of it was not small.
A kind of quiet, unannounced nostalgia for things that had no clean way to be acknowledged.
No one else had been with them. Every piece of pressure had been absorbed internally.
Perhaps it was exactly that unusual bond -- built under unusual conditions, shared only among themselves -- that had given Aizen a particular quality of feeling toward both of the others that went beyond what he showed toward anyone else.
Of course, that kind of sentiment was always brief.
Aizen let out a quiet breath, used the pause to bring himself back, and reset his expression in a practiced motion.
The natural, composed smile returned. His voice carried a note of something close to confidence when he spoke.
"Matsushita-kun. Look at this."
He reached out and pressed one of the instrument panels.
A soft sound, and the whole laboratory came to life. Lights flickered and settled into brightness.
Aizen stood in the center of it, smiling, one hand raised, pointing toward something that had just appeared in the space in front of him.
"Come take a look at this."
Matsushita Yusuke stepped forward and found himself looking at what appeared to be a research document -- dense and structured, written in the format of a theoretical paper.
A framework of reasoning and conclusions related to the problem of power fusion.
He blinked.
His expression went visibly puzzled.
When had Aizen written this? Why had he heard nothing about it?
Aizen seemed to read the confusion clearly, because his mouth curved slightly and his tone took on a mild, slightly self-satisfied quality.
"Nothing particularly worth boasting about. I simply set aside some attention for this problem occasionally. Over time, one thought led to another."
Casually said.
But Matsushita Yusuke understood the real weight behind it.
Aizen was someone who went to sleep dreaming about breaking through his limits. Claiming he didn't think about something like this was not a claim anyone was going to believe. This document had probably taken considerable effort to produce.
In the original story, the breakthrough had appeared almost effortless -- a moment of absolute composure that communicated complete control over every variable. That quality of strength was real and undeniable.
But thinking about it from the other side: that composure was the product of everything that had come before it. The long buildup, the accumulated theory, the investment over years -- all of it had reached a point of readiness, and then the Hogyoku had provided the final catalyst that translated all that preparation into an actual result.
That framing also explained why Aizen, in the original story, had come apart as badly as he had. He had worked and planned and maneuvered and invested everything, and finally reached what should have been the moment that was only ever going to be his. His story, his script, his climax.
And then a kid named Kurosaki Ichigo had appeared out of nowhere, shouted something incomprehensible, and cut him in half.
It was probably in that moment that Aizen had genuinely registered, for the first time, that he was not the protagonist of this story. He was someone else's supporting character.
That particular kind of realization was enough to make anyone come apart.
Though all of that was still a long way off. It was still Aizen's chapter right now. He had time to enjoy it.
Ahem. Back to the material.
Matsushita Yusuke pressed his fingers lightly to his cheek, settled his expression, and began going through the document in front of him.
The content itself was not overly complex. A series of conclusions drawn from various experiments involving Shinigami and Hollow interactions.
He recognized familiar shapes in the reasoning. Certain arguments and conclusions that mapped onto things he had already encountered himself.
"Aizen-sensei, when did you develop this?"
"Recently."
A brief pause, and then an addition:
"Observing what happened with Isshin gave me some perspectives I hadn't had before. Working through those led to some of what you see here."
That tracked.
Matsushita Yusuke gave a small nod, expression thoughtful.
It was roughly what he had expected -- because inside this theoretical framework, he had spotted a conclusion that was considerably more ambitious than the surrounding material.
Based on all failures accumulated to this point, I offer the following conclusion.
Pure power fusion, as an act in itself, is categorically impossible. In fundamental terms, it is equivalent to forcing two incompatible substances together in direct violation of their underlying nature.
Therefore, any viable approach must be built on a different foundation.
Specifically: the inheritance of power.
There it is.
Matsushita Yusuke found the key line.
If two individuals carrying different types of power were to produce offspring, the children of that union might inherit the aptitude to carry both.
Stated plainly, the idea sounded like wishful speculation.
The concept of a Shinigami and a Hollow producing children was genuinely extreme -- before the Arrancar existed, the only Hollow in the world with anything resembling a recognizable face was Barragan, and he was famously not the sociable type.
Quincies pairing with anyone produced results that felt even more unlikely. Given the Thousand-Year Blood War and the relationship between the two sides that it documented, the idea of any three-way combination seemed to operate in defiance of basic historical logic.
Looking at it that way, the whole concept seemed impossible -- there was no obvious path to any of these three groups intermarrying in the first place.
Matsushita Yusuke worked through the full thread and looked up with a thoughtful expression.
"So this is purely theoretical at this stage -- correct?"
Aizen stood beside him and said in a measured, somewhat reflective tone:
"Based on the experimental capacity I had available in recent years, yes, exactly as you say. The conditions required to merge different types of power are extraordinarily restrictive. Theoretically, inheritance is the only realistic pathway."
But.
There were always exceptions.
"If I'm able to obtain the Hogyoku, I may find a different kind of answer."
Not entirely certain in tone. But Matsushita Yusuke, knowing how the story went, understood that this was not idle speculation.
Aizen had, in fact, broken through alone with the Hogyoku's assistance. He had crossed the threshold by himself and reshaped what was possible for a single existence.
Inspiring, in its own way. But outside of that specific path, no other clear opening presented itself. Matsushita Yusuke finished the full document, set it down, and held a quiet, thoughtful expression.
Honestly: a little helpful.
But not by much.
"Still -- you've helped me organize my thinking. Thank you, Aizen-sensei."
Aizen smiled and nodded, raising his right hand to give a light pat on his back.
"Think nothing of it. My research has always been open to both you and Tosen without restriction. If you have any thoughts, I'm genuinely happy to work through them with you. No pressure. Go wherever your thinking takes you."
The visit had taken an unexpected shape, but by the time Matsushita Yusuke left and was walking back toward Squad 11, the trip had produced something real.
His right hand rested on the hilt at his waist as he walked, and the thoughtful expression didn't leave his face.
From where things currently stood, the only clear path to the merge was grinding all three panels to 100.
But what else was there?
Maybe the only remaining angle was to approach the problem the way offspring would.
He rubbed his chin, turning it over.
That line of thinking --
Might actually have some viable possibilities in it.
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