In the distance, Ichimaru Gin braced himself against Zaraki's incoming longsword, while Aizen restricted Zaraki's movements from the left. Judging by their strained expressions, they wouldn't be able to hold him back for long.
In truth, they didn't need to hold him for long. Taking advantage of the opening they created, Kōe struck out with lightning speed, landing two palm strikes directly onto Zaraki's Saketsu and Hakusui.
His speed was incredible, and his targeting was exceptionally precise. However... Gin looked at Zaraki, who hadn't moved an inch from his spot, and thought to himself, *'Did he hit him too lightly?'*
The Saketsu and Hakusui were vital points for Reiryoku, but they weren't fatal pressure points. And even if they were, a simple tap wouldn't be enough to cause any real damage.
To incapacitate an enemy through these two vital points, one would need to inflict visible trauma, if not pierce straight through them. Those two feather-light palm strikes wouldn't even suffice for a satisfying scratch.
Zaraki's Reiatsu grew even more violent. Just as Gin assumed he had been enraged, he noticed something was off.
It was true that Zaraki's Reiryoku control was abysmal—otherwise, the members of Squad 12 wouldn't have had to specially craft an eyepatch to restrict his Reiatsu.
But no matter how poor his control was, it shouldn't have rendered him completely immobile. Was this a case of his internal Reiryoku going berserk? Gin wasn't sure if that was the right way to describe it. After all, this was merely a theoretical possibility mentioned in a research report on artificial souls housed within the Great Spirit Book Gallery.
According to Aizen, the initial research into artificial souls existed to shatter the limits of a Shinigami. The method involved injecting foreign Reiatsu into a body to elevate its power level.
There were many hurdles to overcome in this process, such as ensuring the injected subject's power level increased permanently. Another major challenge was figuring out how to make different Reiryoku compatible, preventing the subject from dying due to their internal Reiryoku going berserk.
Records of this research were scarce, even within the Great Spirit Book Gallery. The original researcher, the former Squad 12 Captain Hikifune Kirio, had already been promoted to Squad 0, making it impossible to investigate the finer details.
Zaraki's current state looked exactly like Reiryoku going berserk. Although the aura he emitted was violent, the turbulence was primarily originating from within his own body. Gin was even a little curious—would this man just spontaneously explode right here in the next second?
If this truly was a Reiryoku rampage, then the Kōe Shihouin standing before them possessed the exact kind of ruthlessness Aizen had described. Perhaps Aizen's assessment that Kōe had surpassed him wasn't just a lie after all.
Injecting Reiryoku sounded simple enough, requiring only two steps: releasing one's own Reiatsu, and then injecting it into the opponent's body. But actually executing those two steps involved far too many difficulties.
Setting aside other factors, just the rapid injection alone was enough to give most people a headache. When Reiryoku of different signatures and structures came into contact, the immediate reaction was absolute resistance, not assimilation. Furthermore, this resistance began the moment they clashed externally.
It was somewhat akin to a deathmatch—either one lived and the other died, or both perished together. There was no such thing as initial symbiosis followed by mutual destruction, like some sort of failed societal assimilation.
Moreover, the stronger the Reiatsu, the more severe the resistance. Different Reiatsu signatures would become as incompatible as fire and water. Simply injecting Reiatsu into someone with Captain-level Reiryoku was already a monumental task, let alone doing it to Zaraki Kenpachi, whose Reiatsu ranked among the absolute highest. Such a feat was practically unthinkable.
However, aside from torturing the enemy, Gin couldn't think of any other benefit to using this method. After all, if Kōe could achieve this, simply subduing Zaraki Kenpachi should have been a trivial matter.
"What a cruel... monster," Gin murmured.
If Kōe could hear Gin's evaluation of him, he would probably jump in fright. *'Wasn't I just trying my best not to hurt Zaraki?'*
What Kōe had done wasn't a Reiryoku injection. Aizen, standing nearby, understood this most clearly. Of course, the method Kōe actually used was just as astonishing.
When different Reiryoku came into contact, the immediate reaction was resistance. Kōe had simply utilized this most fundamental principle, albeit with far greater finesse.
The first palm strike hadn't revealed anything unusual. Aside from its impressive speed, it was flawed—the Reiatsu was dispersed, and the force was lacking.
But when the second palm strike, delivered almost simultaneously, hit Zaraki, its equally dispersed Reiatsu combined with the first strike to produce an unexpected effect.
The Reiatsu within Zaraki's body instantly converged on the space between his Saketsu and Hakusui. Immediately after, it surged outward toward both ends at an extreme speed, violently impacting the two vital Reiryoku points.
Although these two points were major hubs for Reiryoku circulation, they couldn't withstand such a massive volume of Reiryoku flowing through them all at once. Consequently, they began autonomously venting Reiryoku to other parts of his body.
Zaraki's originally somewhat orderly Reiryoku flow was instantly thrown into chaos. While this achieved a partial berserk effect, it caused very little actual harm to Zaraki. His current inability to move was merely his body's natural reaction, doing everything it could to force the disrupted Reiryoku flow back to normal.
It was hard to believe such a dramatic outcome was merely a coincidence caused by Kōe unintentionally. He had used countless small-scale, pinpoint Reiatsu collisions to trigger a calculated convergence of Reiatsu.
Even though the target was a special case like Zaraki, who barely understood how to control his Reiatsu, achieving this required both masterful Reiryoku control and acute Reiatsu perception. Neither could be lacking.
It could even be said that in these two abilities, Kōe had already reached the absolute pinnacle of what a Shinigami could achieve. At the very least, Aizen admitted to himself that he was inferior to Kōe in these two aspects.
This was especially true for his Reiatsu perception. Being able to sense the internal flow of an opponent's Reiatsu was simply too exaggerated; it almost felt like he had transcended the boundaries of a Shinigami.
Was this Kōe's true fighting style? Even Aizen couldn't give a definitive answer. He could only say that this style suited him perfectly.
First was his exceptional natural talent. Some people were born with impressive Reiryoku, like that red-haired boy named Abarai. Others, like Hinamori Momo, were naturally more adept at Reiryoku manipulation. Kōe was clearly a standout among the latter.
Second was his personality—not his outward demeanor, but his true nature.
If one were to liken Reiatsu perception to an elite intelligence officer, and Reiryoku manipulation to a highly disciplined special forces unit, handing them over to a general who only knew how to charge bravely into battle wouldn't necessarily yield good results.
Simply put, such a unit didn't need to overpower the enemy with sheer force, and engaging in head-on clashes was a very low priority. They could rely entirely on superior intelligence to know both themselves and their enemy, pair it with the appropriate tactics, and secure the greatest victory at the smallest cost. It was an overwhelming advantage that rendered brute force entirely useless.
Just like how Kōe was currently binding Zaraki completely with a low-level Bakudō. If the Reiryoku inside Zaraki's body hadn't been thrown into chaos, a low-level Bakudō like this wouldn't have even been able to touch him.
The moment he made a move, the subsequent steps required to achieve his goal were already clearly outlined in his mind. Danger hid within the most inconspicuous details. When facing a man like this, one truly couldn't afford to lower their guard for even a second.
"You really found yourself a troublesome one, Urahara Kisuke," Aizen murmured.