In truth, it was not that the Hogyoku could not undo Hirako Shinji and the others' Hollowfication. Rather, the Hogyoku had read "Urahara Kisuke's" heart. It did not resolve the problem of Hirako Shinji and the others' Hollowfication, only stabilized their condition.
Although the "Hogyoku" had been created by Urahara Kisuke, the current Urahara Kisuke had no idea what the Hogyoku's true abilities were.
He had always believed that the Hogyoku he created could break the limits of a Shinigami's spiritual pressure, allowing Shinigami to undergo Hollowfication and wield the powers of Hollows.
Moreover, Urahara Kisuke was a researcher. When he created the Hogyoku, he had certainly used some of the Shinigami imprisoned by the Second Division to conduct Hollowfication experiments.
But there definitely had not been any Vice-Captains or Captains serving as experimental subjects.
To Aizen, four Captain-level figures and four Vice-Captain-level figures were all "extremely precious experimental materials." He had even thanked Hirako Shinji and the others for "bringing him more experimental data"...
If Urahara Kisuke claimed he did not want to continue researching Hirako Shinji and the others' condition, he would only be lying to himself.
Especially since, when he took out the Hogyoku, Urahara Kisuke had said that he only had a twenty percent chance of curing everyone.
Eight people, with a twenty percent chance.
Given Urahara Kisuke's cautious nature, twenty percent was definitely an understatement.
There should have been at least a thirty or forty percent chance of undoing Hirako Shinji and the others' Hollowfication.
Yet in the end, none of the eight succeeded.
That was no longer a twenty percent chance. It was zero percent.
A total wipeout.
If the Hogyoku had not interfered, Ailin would not believe it even if ghosts told him so.
Now, Urahara Kisuke and Shihoin Yoruichi were using an