There's always been controversy over exactly when the Hōgyoku was implanted into Rukia Kuchiki.
It now appears the second view was correct.
Kisuke Urahara implanted the Hōgyoku into Rukia Kuchiki much earlier.
If Rukia Kuchiki is already over one hundred and ten years old, the implantation might even have happened while she was still alive in the Human World.
Simply put, Hollow White very likely sensed the Hōgyoku inside Rukia Kuchiki, then chose to "transfer" and "merge" with it.
Yoshio couldn't help looking at Aizen.
What would Aizen do?
"That's the Hōgyoku created by Mr. Urahara, right? Is Mr. Aizen planning to extract it?"
Aizen looked at Yoshio and calmly shook his head.
"No hurry."
He gazed at the image of Rukia and said softly, "Aren't you curious what will happen to 'White' after it encounters the Hōgyoku?"
"Mr. Urahara is bold, putting the Hōgyoku right under Captain Aizen's nose, inside the Seireitei."
"In a sense, that's hiding in plain sight, isn't it?"
Kisuke Urahara was exiled to the Human World, so everyone would search the Human World for him and the Hōgyoku, yet he chose to stash something so important in the Soul Society, outside his pursuers' line of sight.
You should know, even if Kisuke Urahara has informants in the Soul Society, they're mainly in the West 6th District of the Rukongai.
But Rukia Kuchiki often appears in South Rukongai, which is also far from Urahara's sphere of influence.
Under normal circumstances, no one would expect Urahara to do this.
"And what about 'White'?" Yoshio asked softly. "Is it fine to just use him on Rukia Kuchiki?"
He was a bit worried—without Hollow White, who would bring Shiba Isshin and Kurosaki Masaki together?
Kurosaki Ichigo can't not exist. If he doesn't appear, is Yoshio supposed to save this world?
Forget it—he has no interest in being a savior.
One difference between the Shinigami world and others is that the protagonist isn't especially crucial to plot progression.
Without Kurosaki Ichigo, Aizen would still execute Rukia Kuchiki to extract the Hōgyoku.
Without Kurosaki Ichigo, after seizing the Hōgyoku, Aizen would still declare war on the Soul Society.
Without Kurosaki Ichigo, Yhwach would still grow within the Wandenreich.
Without Kurosaki Ichigo, the Thousand-Year Blood War would still erupt.
But...
The difference is, without Kurosaki Ichigo, Aizen and Yhwach's plans would succeed, and the Soul Society would fall.
So Yoshio truly hopes Ichigo won't be absent. If he is, does Yoshio have to protect the Soul Society? Fight?
Forget it—he has no interest in being a doctor either. Exhausting! Scraping by is enough.
Besides, when does killing monsters ever end?
After Aizen comes Yhwach; after Yhwach comes Hell. If you're invincible, your enemies eventually descend from the heavens.
Battle never ends—leave that to Kurosaki Ichigo.
Hearing Yoshio's words, Aizen frowned.
To be honest, his research on Hollow White had only just begun.
Hollow White is the first—and so far only—Hollow created from a Shinigami's soul, so naturally there's much to study.
But his frown quickly smoothed out.
"Then we'll just make another."
"After all..."
"It's a consumable."
Based on the data Aizen currently has, even without the [The Animals] provided by Yoshio, he's confident he can create another "White."
It's only a matter of time.
Seeing Aizen so confident, Yoshio nodded as well. With Aizen's ability, recreating Hollow White isn't impossible.
"However, I suppose the Seireitei won't be very peaceful next?" Yoshio asked.
"Just a trifle," Aizen said calmly. "For now, pay more attention to Rukia Kuchiki."
"Mm."
Yoshio nodded.
He stayed in the lab for a while longer, then went home.
…
The next day, he didn't go to the Fifth Division, but headed straight to the Fourth.
Upon arrival, Yoshio entered Jūshirō Ukitake's ward and found Kyōraku Shunsui inside.
Seeing Yoshio enter, Jūshirō Ukitake coughed twice and said, "Thanks this time, Yoshio-kun. If not for you, Kaien, Rukia, and I would probably all have died at that Hollow's hands."
Kyōraku Shunsui also looked over and couldn't help saying, "I didn't expect such a dangerous incident last night—thanks to you, Yoshio."
I don't believe you two!
Ukitake's better—his favorability shot straight up to sixty-six. But you, Kyōraku Shunsui, only jumped from fifty to fifty-five.
Is this what a seasoned schemer looks like?
Forget it—at least it went up.
Victory is within sight; one day, I'll break through your emotional defenses.
Can I reach eighty?
It will.
Yoshio said a bit sheepishly, "Actually, it was mainly Captain Ukitake and Lieutenant Shiba who drained that Hollow's physical and mental strength. Otherwise it wouldn't have fled so decisively."
"It's a pity I'm still too weak and couldn't kill it."
"Don't say that. I heard from Kaien that you and the Kaido saved his and Rukia's lives."
"Where is Lieutenant Shiba? I heard from Hanatarō he's already been discharged?"
When Yoshio arrived, he'd seen Hanatarō and learned from him that Shiba Kaien had already left the Fourth Division.
"...He told me he wants to go to Hueco Mundo," Ukitake said after a moment's silence. "He wants to search Hueco Mundo for that strange Hollow."
"..."
Yoshio also fell silent.
How dangerous is it for a Shinigami to go to Hueco Mundo?
"You agreed?"
"...How could I... refuse?" Jūshirō Ukitake said softly. "I couldn't refuse Kaien's request, so..."
"I'll report this to the Captain-Commander."
"Though I'm not very close with Lieutenant Shiba, we've fought side by side. If this is approved, please inform me before he departs so I can see him off."
"Of course." Ukitake nodded.
Only then did Yoshio say, "Alright, I won't disturb Captain Ukitake's rest. I'll go check on Rukia."
"Mm, go on."
After Yoshio stepped out, he suddenly saw Kuchiki Byakuya coming out of Rukia's room.
Kuchiki Byakuya saw Yoshio as well. Although he appeared indifferent, Yoshio could see his favorability toward him...
Already at 72!