Captain-Commander Yamamoto approved Aizen's request.
Since this was proposed by Aizen but involved some specialized knowledge, the Fifth Division and Twelfth Division would jointly examine all of Kisuke Urahara's past experiments.
They would see if they could find any clues from these experiments.
As for the other squads, they were to strengthen defenses and absolutely not allow something like this to happen again.
How much pressure Captain-Commander Yamamoto would face from Central 46 upon returning was no longer Yoshio's concern.
Afterward, he would head to the Daireishokairō with Aizen.
Since this entry was legitimate, they also needed authorization from the first administrator.
Of course, Yoshio didn't need to worry about these things.
Dealing with nobles was definitely a high-level matter.
Once Aizen finished handling things, Yoshio couldn't help but smile. "Speaking of which, this is our first time entering the Daireishokairō legitimately, huh?"
Aizen smiled without saying a word.
The Daireishokairō was indeed not an easy place to enter; it held too many secrets of Soul Society.
Soul Society had too many unspeakable secrets.
The simplest one was creating the Ōken...
You see, what Aizen saw in the Daireishokairō wasn't the method for making the Ōken, but the process of making the Ōken!
So, what is the process for making the Ōken?
One hundred thousand souls, and Double Spiritual Ground!
In other words, someone in Seireitei had already done this before Aizen!
Through a special spiritual technique, one hundred thousand souls can be combined with a Double Spiritual Ground to form the Royal Key, also known as the "Ōken."
Of course, there's another way to make the Ōken: using Soul King's Power to reshape a Shinigami's body. The bones and hair of the rebuilt Zero Squad are the Ōken.
Aizen wanted to use Double Spiritual Ground and one hundred thousand souls to create the Ōken, which essentially meant he wanted to turn himself into a member of the 'Zero Squad.'
And "Soul Society" had obviously done something like this before.
For example, Captain-Commander Yamamoto knows the location of one Ōken. This Ōken probably wasn't purified by Soul King's Power but was made using the "Ōken creation method" that Aizen wanted to use.
In other words, "Soul Society" had done it once before "Aizen."
Soul Society had done it too!
But of course, such things couldn't be leaked, after all, for the propaganda to ordinary people, they still needed to maintain their glorious and just image, allowing them to proudly appear as balancers of the world to ensure the organization's cohesion.
This time, their entry into the Daireishokairō was strictly limited by the first administrator; they could only query records related to Kisuke Urahara, and nothing else.
This restriction was meaningless to Aizen; for him, there was no place in Soul Society he couldn't go, but entering openly was indeed rare.
The Fifth Division followed the Twelfth Division over. When Aizen opened the Daireishokairō, some technicians from the Twelfth Division entered along with the captain and lieutenant of the Fifth Division.
Aizen and Yoshio entered, ostensibly because Aizen had proposed this and was there to observe, but in reality, to monitor Mayuri Kurotsuchi.
Although Mayuri Kurotsuchi was the captain of the Twelfth Division, his behavior and ideas were too dangerous to be trusted.
So Captain-Commander Yamamoto ordered Aizen to come along specifically to monitor Mayuri Kurotsuchi and prevent him from causing trouble.
Such things couldn't be said openly, but for Shinigami who had lived for hundreds of years, everything was understood without words.
After entering the Daireishokairō, Yoshio looked at its structure, which resembled a supercomputer, and couldn't help but want to complain.
Although the Daireishokairō was a supercomputer, aside from the screens, the surrounding structures were all wooden—truly advanced yet ancient, worthy of Seireitei.
Yoshio ignored the Twelfth Division and found a screen for himself, wanting to see if there was anything fun.
Of course, he could only search for Kisuke Urahara's research data.
Kisuke Urahara was indeed a genius, especially after establishing the Research and Development Institute, where various creations gushed out like a fountain.
Unfortunately, his time as director was too short—only nine years. If it had been longer, who knows how many more interesting things he could have invented.
After a while, he even discovered research related to the Hōgyoku.
If Mayuri Kurotsuchi saw this, who knows what that guy would do, but when Yoshio looked, he found that Mayuri Kurotsuchi seemed to completely ignore the Hōgyoku.
With his abilities, it's impossible he couldn't see the research value of the Hōgyoku, yet he casually skipped over it...
This indicated...
Yoshio glanced at Aizen, who was standing beside Mayuri Kurotsuchi at the moment, looking as if he knew nothing about the research.
Yoshio knew that Aizen must have used Kyōka Suigetsu to alter what Mayuri Kurotsuchi was seeing.
Yoshio then stopped paying attention to these things and focused on Kisuke Urahara's research content.
For him, who aspired to become a scientist, having Kisuke Urahara's research data would be extremely helpful in becoming a super scientist.
Among them, he discovered many inventions that he thought he could replicate himself when he had time.
After about five more minutes, Mayuri Kurotsuchi suddenly let out a slightly sinister laugh.
"How interesting, Kisuke Urahara."
Mayuri Kurotsuchi looked at the data in front of him and sneered coldly, "And there's this."
Yoshio looked over curiously and found that what he was viewing was a Hollow.
"This is..."
Aizen asked with some 'confusion.'
"Hmph..." Mayuri Kurotsuchi snorted coldly but still explained to Aizen: "This is called 'Parasite Hollow,' a special Hollow modified by Kisuke Urahara. It can parasitize any spiritual body, and once it does, it completely hides itself."
The Hollow's appearance was a bit like a small snake, and combined with its abilities, it reminded Yoshio of the Parasite Hollow from the Dark Rukia movie.
Does this Parasite Hollow really exist in the living world?
But in the movie, this Hollow ultimately escaped from the Research and Development Institute, yet the data here shows that Kisuke Urahara eventually deemed this Hollow too dangerous and stopped the research, even destroying the experimental subjects.
"Captain Kurotsuchi, do you mean..." Yoshio tentatively asked.
But Mayuri Kurotsuchi directly interrupted: "Don't try to guess my thoughts with your intelligence! I really don't understand why those guys sent you two, who know nothing about technology, here!"
Heh, no one in the world knows more about Kisuke Urahara than me—er, than Aizen. If not us, then who?
Yoshio muttered inwardly but said nothing on the surface.
Didn't you see Aizen didn't say anything either?!
Yoshio noted down the experimental records related to the Parasite Hollow, planning to try it himself after returning to Hueco Mundo.
Meanwhile, Aizen was researching methods to extract foreign objects from souls, preparing for the future extraction of the Hōgyoku from Rukia Kuchiki's body.
Next, Mayuri Kurotsuchi became somewhat impatient. He seemed disdainful and annoyed by Kisuke Urahara's research.
Yoshio particularly noticed that Mayuri Kurotsuchi appeared extremely irritated upon seeing Kisuke Urahara's research records on soul evolution, as if he was very dissatisfied with Kisuke Urahara.
Yoshio guessed he must have seen parts of Kisuke Urahara's experiments that surpassed his own; otherwise, Mayuri Kurotsuchi wouldn't be so frustrated.
Finally, Mayuri Kurotsuchi snorted coldly and, without another word, walked straight out of the Daireishokairō.
Yoshio glanced at Aizen, who innocently spread his hands.
"Well, that's that."
Yoshio said, "It seems Captain Kurotsuchi has a deep prejudice against Kisuke Urahara."
"Did I say that?"
Suddenly, Mayuri Kurotsuchi turned around, looking at Yoshio with a very dangerous gaze.
"...Alright, don't make things difficult for my lieutenant, Mayuri," Aizen said at this point. "Right now, the most important thing is to resolve the hidden dangers in Seireitei and crush Kisuke Urahara's conspiracy."
"Hmph."
Mayuri Kurotsuchi snorted coldly and left with the Shinigami of the Twelfth Division.
Yoshio shrugged indifferently and then left the Daireishokairō with Aizen.
Half an hour later, the captains of the Fifth Division and Eighth Division, along with members of the 22nd Division, appeared in the office of the 18th Division.
Mayuri Kurotsuchi faced Yamamoto Genryūsai, who was seated in the main position, and said: "In Kisuke Urahara's research, I did find some interesting things."
He lightly moved his palm, and the next moment, a light screen projected from his hand.
The data that appeared was the Parasite Hollow.
Mayuri Kurotsuchi said: "First is the 'Parasite Hollow.' Considering that Kyōraku Shunsui said the guy was wearing a Hollow mask, there's a 60% possibility."
"Parasite Hollow?" Yamamoto Genryūsai frowned and couldn't help but say, "What is that?"
"You can tell from the name, right?" Mayuri Kurotsuchi's gaze was unkind. "Then I'll be blunt: perhaps someone in our squad has already been parasitized."
"Who could it be? Kyōraku Shunsui, who was attacked? Suì-Fēng, who was in charge of security? Or..."
"Enough!" Before Mayuri Kurotsuchi could finish, Yamamoto said in a deep voice: "Don't say such things without evidence."
"What a pity," Mayuri Kurotsuchi said with a hint of sarcasm. "Originally, these two were the most suspicious."
"Captain Kurotsuchi, you must have seen more than just this, right?" Aizen interjected at this point.
"Hmph, then it's this." Mayuri Kurotsuchi swiped the light screen, and the Parasite Hollow immediately transformed into a special device: 'Tenshintai'!
"This is called Tenshintai, also an invention of Kisuke Urahara. Its effect is to create an imaginary body with one's own memories and combat abilities, used for combat training."
"Oh?"
"Although theoretically it doesn't last long, I think with slight modifications, the duration could be extended. Most importantly, whether Kisuke Urahara used Tenshintai or not doesn't matter."
Mayuri Kurotsuchi said coldly: "We just need to know that Kisuke Urahara has the ability to create 'clones' of all of us, and that's enough."
His words were clear: Whether Kisuke Urahara used Tenshintai or further modified it, this thing proved that Kisuke Urahara had such capabilities!
In this case, whether you've done it or not is irrelevant; what's important is that you have the ability to do it!
"Then what's the solution?" Yamamoto asked.
"The simplest way is to wait for it to dissipate naturally," Mayuri Kurotsuchi said. "An imaginary body is ultimately just imaginary; it can't exist forever. Based on the Tenshintai's effects, maintaining the imaginary body requires consuming the spiritual pressure of the person sustaining the Tenshintai effect."
"Even if Kisuke Urahara modified it, it's impossible to provide 'infinite spiritual energy' to ensure their eternal existence."
Yoshio inwardly agreed with Mayuri Kurotsuchi's judgment. As expected of Mayuri Kurotsuchi; he understood Kisuke Urahara's abilities very well and was quite knowledgeable about the power of various tools.
But he could never explain the existence of Roka Paramia.
Indeed, the people created by Roka Paramia's ability couldn't exist permanently and would dissipate once spiritual energy was exhausted. However, compared to mere imaginary bodies, they could indeed survive much longer.
After ability fusion, combined with the Hōgyoku's effects, the imaginary body's existence time could reach an astonishing one month!
"We don't have time to wait," Yamamoto said coldly. "Is there a second method?"
"Make the person maintaining the Tenshintai stop inputting spiritual energy, or destroy the Tenshintai," Mayuri Kurotsuchi said indifferently.
"I'm quite puzzled," Aizen asked at this point. "Captain Kurotsuchi, you seem to have been considering the possibility of a traitor among 'us.' Why is that?"
"Hmph, because that's naturally the only possibility," Mayuri Kurotsuchi said again. "Ever since the Eighth Division captain was attacked, the entire Seireitei has been under my surveillance. Do you think anything could escape my monitoring?"
"From the beginning until now, no 'unfamiliar faces' have appeared in Seireitei. You know what that means, right?" Mayuri glanced at Aizen.
Aizen remained silent.
It means that everything happening now is caused by 'familiar culprits'?
Hacking into surveillance in one area might be possible, but hacking into the entire Seireitei's surveillance? Wouldn't that mean the Research and Development Institute is full of idiots?
Actually, Yoshio really wanted to say that if the opponent was truly Kisuke Urahara, couldn't he hack into your surveillance system and modify it at will?
But if he said that, "Mayuri Kurotsuchi" would definitely go on a "rampage," right?
Isn't that blatantly saying your technology is inferior to Kisuke Urahara's?
Yamamoto probably had similar thoughts, but he didn't say them out loud either.
And honestly, although Mayuri Kurotsuchi's technology was indeed a bit inferior to Kisuke Urahara's, casually hacking into Mayuri Kurotsuchi's system wasn't that simple.
Especially when Mayuri Kurotsuchi himself was being serious.