After settling the thoroughly drunk Orihime Inoue in, Rukia Kuchiki stayed behind at the 4th Division to keep her company, while Muten Natsu went to the 2nd Division to find Yoruichi Shihōin.
"Muten Natsu?" Suì-Fēng had just stepped out of the VIP room, almost without making a sound. "What are you here for?"
"There's something I want to ask Yoruichi-sama." Muten Natsu noticed the faint blush that still lingered on Suì-Fēng's face. "Am I interrupting?"
"Yoruichi-sama is resting." Suì-Fēng stood in front of the door with a frown, clearly unwilling to let anyone disturb her.
"I get it." Muten Natsu understood how irritating it was to be bothered while sleeping, so he turned to leave. "Then tell her for me later... actually, never mind. I'll ask after we get back to the World of the Living."
There was no need to rush.
Better not disturb them.
As the Captain of the 2nd Division, Suì-Fēng did not have a very good impression of someone like Muten Natsu, who had been thrown into prison several times.
But the moment she heard him say that, her gaze softened noticeably.
"Muten Natsu?" Yoruichi Shihōin heard the voices and came out scratching the back of her head. "Feels like every time you come looking for me, it's because something happened."
Suì-Fēng's expression toward Muten Natsu immediately lost some of that softness.
"Come in." Yoruichi Shihōin yawned as she turned and walked back inside. "You want to ask about the Hōgyoku, right?"
"Yeah." Muten Natsu stepped into the VIP room. "When Rukia was in trouble, you should already have known Aizen was making his move, and that his target was the Hōgyoku. So why did you still help me come to Soul Society?"
Yoruichi Shihōin dropped casually onto the sofa, took the teacup Suì-Fēng handed her, and sipped from it. "Given the state you were in back then, even if he had tried to stop you, you would've found some other way to get to Soul Society. Since you were coming no matter what, it was better for him to help. That way, the odds of success were higher. But the most important point is..."
Yoruichi Shihōin frowned, scratching at her hair, obvious confusion in her eyes. "I remember the Hōgyoku being hidden inside Rukia."
"You remember?"
Meeting Muten Natsu's eyes, Yoruichi Shihōin answered, "I'm the one who hid it."
Suì-Fēng looked at Muten Natsu, visibly tense.
She had also heard some of what Sōsuke Aizen said atop the Sōkyoku.
You could say that most of what Muten Natsu had gone through was because the Hōgyoku was inside him.
And now Yoruichi Shihōin was openly admitting that she had hidden the Hōgyoku...
Muten Natsu's expression did not change. "Can you explain in more detail?"
Yoruichi Shihōin tilted her head. "Hm... that's really all the reaction you've got?"
"Wasn't your intention to hide the Hōgyoku inside Rukia?" Muten Natsu sounded perfectly calm. "Which means the fact that it ended up inside my body wasn't something you did on purpose."
"But I did want to hide the Hōgyoku inside Rukia. You two are so close. Aren't you angry?"
"There was no Hōgyoku inside Rukia."
"Huh... what?" Suì-Fēng felt that something was off, but she could not quite put it into words.
"Because of the Hōgyoku, I've been through a lot." Muten Natsu looked down at his own palm. "But if it weren't for the Hōgyoku, I might have died long ago."
"When I first saw the Hōgyoku... it didn't even have a name yet." Yoruichi Shihōin got straight to the point, gesturing with her hand. "It was just a round bead about the size of a walnut. Kisuke told me it was something that could break the boundaries of Shinigami, but even he didn't know how he had created it."
Muten Natsu let out a small questioning sound. "Hm?"
"You know what a Gigai is, right?"
Muten Natsu answered at once, "A high-density Reishi body."
"Kisuke explained the principle to me before, but I don't remember it that clearly. Ask him yourself later." Yoruichi Shihōin thought back carefully. "More or less, it means stably combining a large quantity of Reishi so it can absorb Reishi from the atmosphere and help a soul recover its strength. After breaking Reishi down as far as possible, Kisuke used Reiatsu fusion techniques to stabilize it, trying to create a more precise Gigai that was better suited to a Shinigami. A Gigai that could not only heal a soul, but also strengthen it. And as a result, the Hōgyoku appeared."
"The experiment failed." Muten Natsu caught the subtle tone in her voice. "But it was even more successful than a success?"
"Exactly." Yoruichi Shihōin tapped the rim of her cup. "He discovered that the Hōgyoku had the power to instantly destroy the boundary between Shinigami and Hollow. That power made Hollowfication possible for Shinigami."
Spiritual power gathered at Yoruichi Shihōin's fingertips, forming into a small sphere that sank into the tea. "If you put a Hollow soul into another soul like this, then erase the boundary..."
The spiritual power instantly spread through the tea, making the liquid in the cup churn violently. "That soul becomes stronger."
Muten Natsu nodded. It was easy enough to understand.
Like a small bread roll—if you swallow it without unwrapping it, it will harm your body rather than help it.
But if you tore the wrapper open first and ate it, then your body could digest it and turn it into the energy it needed.
"But there's a problem." Yoruichi Shihōin moved one finger, and a burst of spiritual power shattered the teacup. "When an ordinary soul mixes with a Hollow soul, it turns into a mindless monster. And... as Hollowfication deepens, not only does the boundary within the soul collapse, but the boundary between that soul and the outside world collapses too. Consciousness separates from the self and eventually disappears completely. Kisuke called that [Soul Suicide]."
A light screen kept refreshing before Muten Natsu's eyes as Myōki used the new information for further deduction. Combined with the conclusions it had already reached, the final result was displayed before him.
The small bread roll had turned into the T-virus.
"Once Kisuke realized that this power and the technology behind it were impossible to control, he gave up on destroying the Hōgyoku and could only place a barrier around it instead." Yoruichi Shihōin brought up what Shunsui Kyōraku had mentioned earlier. "Aizen Hollowfied several Captains and Lieutenants, then pinned it on Kisuke when he tried to treat them. I took them to the World of the Living and hid them away. While Kisuke was searching for a way to reverse Hollowfication, he kept researching the Hōgyoku, and during that process, he discovered something terrifying."
"Something terrifying?"
"All of his experiments were going far too smoothly."
Muten Natsu looked puzzled. "That's terrifying?"
Yoruichi Shihōin tugged at the corner of her mouth. "Do you know what a Jūreichi is?"
"A spiritual anomaly point located in the World of the Living." The light screen before Muten Natsu displayed knowledge taught at the Shin'ō Academy. "Its location changes over time. It's a spiritually unusual land in the World of the Living where souls gather most easily... Karakura Town?"
"Karakura Town wasn't originally a Jūreichi. But when Kisuke wanted to carry out an experiment that required one... Karakura Town became a Jūreichi."
Suì-Fēng suddenly realized a possibility so absurd she barely dared believe it. "Could it have been the Hōgyoku?"
"That's right." Yoruichi Shihōin's expression stiffened slightly. "That damn thing reads the hearts of the people around it and turns them into reality. It's not that the Hōgyoku itself had the power to destroy the boundary between Shinigami and Hollow. It's that Kisuke wanted something with that power. Chad and Orihime's powers came from the same thing, because they wanted power. And you, Muten Natsu... your Hellfire, your Hollowfication, your two Zanpakutō... those were probably born because the Hōgyoku read your heart and manifested the desires buried inside it."
Everything from the past flashed through Muten Natsu's mind.
When he faced the Lizard Hollow, he wanted power, so Hollowfication began, and he gained Hellfire.
After killing the Lizard Hollow, he wanted to heal himself, so the Lizard Hollow was refined into a Remnant Spirit Weapon.
After entering Seireitei, he wanted to understand everything around him better and faster, so Myōki began to function, gathering and organizing information from his surroundings.
When he was trapped in Hueco Mundo, he wanted to gather everyone's strength and break out together, and that gave rise to the ability to seize souls.
When he was locked in prison and Bokukō was taken away, Muten Natsu wanted a second Zanpakutō that could not be confiscated, and Myōki manifested in his left arm.
When he was framed, he wanted the power to uncover the truth, and Bokukō gained the ability Shadow Stealth.
Muten Natsu found it hard to describe how he felt at that moment. "So I once... had the power to make whatever I wanted come true?"
And even then, he had still lived such a hard life.
If he had been a little bolder, wanted a little more, then maybe now...
"Kisuke had the same thought before, but the Hōgyoku's power has limits." Yoruichi Shihōin understood exactly how he felt. "The Hōgyoku can manifest the desires in the hearts of those around it, but the target itself must already have the potential for it. What the Hōgyoku has is the ability to push reality in the direction someone hopes for."
Just like how Muten Natsu once wanted Takuma and Kaien to survive, but they still died.
With that condition added, Muten Natsu immediately felt that the Hōgyoku's power was not all-powerful after all.
If I already had that ability myself, there would be no need for the Hōgyoku to manifest it.
But when he thought about it carefully, even with such heavy restrictions, that power was still absurdly strong.
In theory, everyone has the ability to write beautifully.
In reality, not everyone can produce beautiful handwriting.
There is a very long road between being able to do something and actually accomplishing it.
For all kinds of reasons, many people never make it to the end of that road.
But the Hōgyoku could make that road disappear.
The moment he realized that, Muten Natsu immediately understood what Yoruichi Shihōin meant by terrifying.
As a researcher, there were simply too many things Kisuke Urahara wanted to do, and too many things he was capable of doing.
Among them were more than a few frightening possibilities.
"Looks like you figured it out." Yoruichi Shihōin continued. "Afraid that the thoughts in his heart might become reality, Kisuke handed the Hōgyoku to me after finishing his final experiment and asked me to hide it inside a soul in Soul Society."
"Why a soul in Soul Society?"
"What did they teach you in school?" Yoruichi Shihōin asked. "About why Konsō is necessary."
"The Reishi in the atmosphere of the World of the Living is too thin. A soul's power disperses faster there, and eventually a Hollow Hole will form. That's why souls are sent to Soul Society with a Zanpakutō. During that process, the Chain of Fate is removed, and the denser Reishi in Soul Society's atmosphere suppresses the loss of spiritual power and prevents Hollowfication." Muten Natsu understood immediately. "A soul in the World of the Living that has not undergone Konsō is far more likely to Hollowfy than a soul in Soul Society. And with the Hōgyoku's influence added on top of that, it might produce an extremely powerful Hollow."
"So Kisuke used a Senkaimon he created himself to bring the uncontrollable Hōgyoku into Soul Society, then casually placed it into a soul." Yoruichi Shihōin went on. "He developed a device for it, so the whole thing could be completed while the soul was asleep. The Hōgyoku's power is strong, but as long as the soul doesn't know it exists, it basically has no negative effect on them."
"Did something go wrong during that process?"
"That's the heart of the problem. Nothing went wrong. The whole thing went unbelievably smoothly." Yoruichi Shihōin still could not understand it. "So why did it end up wrong?"
Yoruichi Shihōin remembered it clearly. It should have been placed inside the infant Rukia.
A translucent display appeared before Muten Natsu's eyes. He paused slightly.
"Soul Essence Stealing?"
"You mean your Zanpakutō's ability?"
"Yeah. Back in Hueco Mundo, I used Soul Essence Stealing on Rukia," Muten Natsu said, thinking it through. "Maybe that's when the Hōgyoku was transferred into my body. Can the Hōgyoku even be moved through Soul Essence Stealing?"
"How would I know? Ask Kisuke when you get the chance." Yoruichi Shihōin rested her chin on her hand. "Either way, the Hōgyoku was created by a Shinigami. It's not impossible for it to be affected or transferred by a Shinigami's ability."
"There's something else." Muten Natsu recalled what he had seen earlier. "When the Hōgyoku was taken out, I saw Hellfire burning on it. If it's been scorched by those flames… could it change somehow?"
"Ask Kisuke."
"..." Muten Natsu stood up. "Then we'll talk about it after we return to the World of the Living."
After staying in Soul Society for several days, it was about time to head back.
...
Junrinan, West Rukongai.
Yasutora Sado carried Shibata Yuichi over his shoulder as they walked along a narrow path by the river.
"Shibata… are you happy here?"
"I am. My family treats me really well."
"Family?"
"Soul Society… more precisely, Rukongai. Most people here are strangers, but they live together like families." Shibata Yuichi hugged Yasutora Sado's head. "Rukongai is huge, and all kinds of people live here. Everyone died at different times and places, so it's really hard to run into relatives who've passed away."
"So… you still haven't found your mom?"
"…Yeah."
"Don't worry." Yasutora Sado caught the tremble in his voice. "You've got a new family taking care of you, and your mom will too. If you're still worried, just keep looking. One day, you'll find her."
"Yeah!" Shibata Yuichi nodded firmly, then looked off into the distance. "The sunset is really beautiful."
"I… think so too." Yasutora Sado gazed at the mountains, glowing red under the setting sun.
"Mom must be… somewhere… watching this same sunset."
"…Yeah." Yasutora Sado gently set Shibata Yuichi down, then knelt on one knee and looked him straight in the eyes. "Shibata… even if you're apart right now, there will definitely come a day when you can watch the sunset together with your mom."
"What about you, Uncle?" Shibata Yuichi looked up at him. "Will we… meet again someday, not because of death?"
"…We will."