Simply put, the execution stand and the halberd together formed the Sōkyoku. The halberd, which supposedly possessed an offensive power equivalent to a million Zanpakutō, was stabilized by the execution stand, which possessed an equal amount of defensive power.
The two complemented and restricted each other. The halberd could not be seized by anyone because it would only attack whatever was on the execution stand. Therefore, theoretically, seizing the Sōkyoku meant taking the execution stand along with it. Could such a thing be used as a weapon in actual combat? Obviously not.
Was there a possibility of seizing the halberd alone? Perhaps, as long as the Sōkyoku's halberd could be freed from the execution stand's control. Unfortunately, the execution stand was also the mechanism that maintained the halberd. Its exceptional defensive power made it nearly impossible to destroy, and even if it were destroyed, the power within the halberd would rapidly dissipate, turning it into a pile of scrap metal.
Thinking about it this way, the very idea of stealing the Sōkyoku was laughable. Even if one succeeded, the cost would far outweigh any benefits the Sōkyoku itself could provide. It sounded utterly absurd.
Because of this, Kōe would never forget the uncontrollable laughter Yoruichi had let out when he first brought up the idea of stealing the Sōkyoku, nor her soul-piercing rhetorical question: "In all of history, did you really think you were the only clever little genius?"
He had wanted to throw those exact same words right back at Hitsugaya just now. The Sōkyoku had been sitting there for over two thousand years—use your brain and think about why no one had stolen it! As if he was the only clever little genius around!
He was still too young. It was easy to imagine that when Hitsugaya tried to use this argument to persuade Old Man Yama or Central 46 to halt the execution, he wouldn't receive any response at all.
And if he stubbornly insisted, he might even be seen as assisting the Ryoka. Kōe believed that Hitsugaya probably couldn't think on such a deep level, but with Hinamori weighing heavily on his mind, he would never choose to directly rescue Rukia during the execution. Instead, he would try to solve the problem from what he perceived to be its root.
Trespassing into the already sealed Central 46—this was an entirely predictable course of action, and one he would only be forced to take right before the execution.
Aizen's suicide note, which seemingly created trouble for himself, was something only Hitsugaya would fight for. It was a collar designed specifically for that little lion, though the boy himself couldn't figure it out. The purpose, of course, was simply to keep Hitsugaya away from the execution grounds.
Naturally, this was the original script. With just a few strokes of a pen, Aizen had effortlessly tossed a bone to the little lion. As long as Kōe showed his face, Hitsugaya would absolutely bite down and refuse to let go, annoying him to death.
"This place of yours really is a great spot to slack off. It's very quiet."
Aizen looked up at Kōe, who seemed to be complaining to him the moment he walked through the door, and replied with a smile, "That is why I invited you over. But you didn't agree at the time, did you?"
That was the truth. There was actually one true statement in Aizen's suicide note: he really had gone to see Kōe that night, and they had indeed met.
"So, is this the second invitation? I can't say I like this method." Kōe didn't plan on beating around the bush and cut straight to the chase. "Where is Shiba Miyako right now?"
"Are you no longer hiding it at all?"
"Since Captain Aizen doesn't plan on hiding himself anymore, I might as well be frank." Kōe spread his hands, speaking with a helpless tone. "Besides, even if I didn't show it, you've already guessed it, haven't you?"
Aizen nodded. When he had gone to Squad 4 to invite Kōe to complete the final step of seizing the Hōgyoku with him, Kōe had decisively rejected him. He stated that he wanted to remain in the Seireitei, and as a trade-off, he would give up on taking the Hōgyoku.
Aizen had considered this outcome, but what followed made Kōe's past actions completely incomprehensible—namely, what was the point of their temporary cooperation?
Since he didn't want to control the Hōgyoku, there was naturally no need for him, having come at Urahara's request, to make contact with Aizen. Was it for self-preservation? No, he should have been well aware that as long as the Hōgyoku remained incomplete, his life was not in danger.
Thinking carefully, if Kōe hadn't cooperated with him back then, what would be the only difference? The answer was obvious: the safety of Shiba Miyako and Shiba Kaien.
Furthermore, over the years, even after learning that the Hōgyoku was not inside Shiba Miyako, Kōe hadn't killed her. If he had planned to stay in the Seireitei all along, leaving behind such a vulnerability was not a wise move.
Aizen did not think the other man was indecisive. For such a situation to occur, there was only one possibility: this vulnerability itself was something Kōe could not bring himself to abandon.
It was an easy deduction to make, yet it was hard to imagine that such cliché sentiments would appear in someone like Kōe Shihouin.
"Since Shiba Miyako is so important to you, now that you've told me, do you think I will return her to you, Kōe?" Aizen smiled, resting his chin on his hand as he spoke earnestly. "Wouldn't it be more advantageous for me to create trouble for a destined enemy?"
"Hehehe." Kōe suddenly burst into laughter. *To think Aizen actually considers me an enemy. I really don't know whether I should be happy or sad about that...*
"That will only anger me, and that wouldn't be a good thing for you, Aizen."
"Anger only reveals flaws. Such a threat is all bark and no bite; it actually makes one want to laugh, Kōe."
"I'm not like that brat Hitsugaya. I have the ability to turn my anger into blood—anyone's blood. Don't you believe me?"
Aizen didn't answer. He looked at Kōe with full interest, as if he were highly anticipating the other's explanation. He was truly looking forward to it.
"I was thinking the whole way here—why did you absolutely have to choose Hitsugaya? Was it because Hinamori made him easy to use? I don't think so. Without that suicide note, with that brat's abilities, he would never have discovered your existence, much less gone out of his way to assist the Ryoka."
"It was enough to force you to come here," Aizen replied slowly.
Kōe shook his head. "No, there were better choices. You only needed to name Shunsui or anyone else as your murderer, and he would have taken similar actions. The only difference is that you knew Shunsui would definitely be at the execution site, and Hitsugaya, retaining some level of rationality, would likely choose to keep an eye on him and head to the execution grounds as well."
"Oh?" Aizen narrowed his eyes, summarizing Kōe's point. "In other words, I actually didn't want Hitsugaya to appear at the execution grounds, correct?"
"But why? What difference would Hitsugaya's presence make to you? If we're talking about combat power that could potentially stop you, I imagine your focus should be on Old Man Yama, but stopping him is nearly impossible. So, what exactly makes that brat so different?"
"It wasn't until just now that I figured it out." Kōe chuckled softly, pointing at his own Zanpakutō. "It's Hyōrinmaru, isn't it? That ability to alter the weather might cause you quite a bit of resistance. After all, Captain Aizen's method of leaving the Seireitei isn't through a gate on the ground, is it?"
"Hahaha, I'm starting to believe it now. You and Hitsugaya are indeed different."
Aizen nodded, replying with a smile, "You guessed everything correctly, Kōe."