Months later, at the Department of Technological Development.
"Katori-taichō, is Sojun's Reishi Shell ready to be used?"
Kuchiki Ginrei examined the cultivated Reishi Shell lying inside the pod—an exact replica of Kuchiki Sōjun.
On the surface, there was no visible difference. Even its Reiatsu fluctuations were highly similar—just significantly weaker, not even reaching the level of an ordinary Shinigami foot soldier.
"This Reishi Shell just has low Reiatsu, but its internal organs have fully developed. It's ready for organ transplantation," Nanatsuki replied.
Kuchiki Ginrei had successfully persuaded Central 46 to revise the ban on Reishi Shell technology.
Now, the Department of Technological Development could manufacture Reishi Shells for the purpose of treating physical disabilities.
However, the nobles remained wary of the technology. All Reishi Shells had to be destroyed after their medical use was completed.
"Then I'll leave it in your care, Katori-taichō," Kuchiki Ginrei nodded slightly.
Nanatsuki had summoned Ginrei today specifically to inform him that the surgery could take place.
Since the transplant wasn't related to the Spiritual Pressure Core, and didn't involve the burden of housing full Reiatsu, the cultivation of Sōjun's Reishi Shell hadn't taken long.
"Akita, go notify Squad Four to bring Sōjun over."
"Yes!"
During the cultivation period, Kuchiki Sōjun had been recovering in Squad Four's care. Akita promptly departed to fetch him.
Moments later, Squad Four personnel arrived with Kuchiki Sōjun.
They were familiar faces to Nanatsuki—Unohana Retsu, Kotetsu Isane, and Hoshino Rie.
"Sensei, we've brought Vice-Captain Kuchiki," said Isane, pushing the wheelchair.
Unohana often brought Isane along with her, as she held her in high regard.
Hoshino Rie was now an officer in the medical division and one of Unohana's most capable assistants.
Sōjun looked visibly better than before—after a period of care in the medical unit, some color had returned to his face.
However, his organs had suffered irreversible damage. His current state was being maintained purely through medication.
"Katori-taichō, I leave it to you—cough, cough—"
Sōjun couldn't even finish a full sentence before coughing up a mouthful of blood.
"Don't worry. This surgery isn't difficult. You just need to sleep through it, and you'll be healed," Nanatsuki said with a gentle smile. "Akita, take Vice-Captain Kuchiki to the medical room."
Over time, Nanatsuki had come to realize that Akita was more suitable as an assistant than either Urahara Kisuke or Mayuri Kurotsuchi.
Both Urahara and Mayuri were too independently minded.
Thus, Nanatsuki assigned them to lead their own respective departments and research teams, while Akita served as his direct research assistant.
"Captain Unohana, thank you for coming," Nanatsuki greeted.
"This is the first Reishi Shell transplant since the ban was lifted. I wanted to witness it myself," Unohana replied with a smile.
"With you present, Captain Unohana, nothing will go wrong," Nanatsuki nodded.
"Don't mind me. I'm just observing," Unohana said, shaking her head.
"Then please follow me. Akita should've already prepared the operating room."
After some small talk, Nanatsuki led them to the medical chamber.
Inside, Akita had already prepared the surgical environment. Sōjun and the Reishi Shell lay on adjacent operating tables.
Tubes ran from both bodies, channeling a liquid rich in high-density Reishi into them.
Nanatsuki, Isane, and Rie all put on surgical gloves.
Nanatsuki would personally lead this operation, but in the future, such surgeries would become routine and be handled by Squad Four. The Department of Technological Development would only supply the organs.
Unohana brought Isane and Rie along to help them gain experience with Reishi Shell organ transplants.
"Captain, anesthesia is in effect. We have a three-hour window," Akita reminded.
"Akita, Rie—start by removing the Reishi Shell's liver." Nanatsuki did not accept the scalpel from Isane. "Isane, you handle the incision."
"Me… me?" Kotetsu Isane panicked slightly.
This was her first time participating in a major surgery. Her nerves were getting to her.
"I'll be guiding you," Nanatsuki smiled.
Isane stepped up to the table, preparing to make the incision.
"Once you've found the right spot, don't hesitate," Nanatsuki reminded her upon seeing her hesitate.
"Yes!" Isane nodded firmly, pumping herself up.
With precision, she located the spot and successfully opened Sōjun's abdominal cavity.
His lungs hadn't further deteriorated, but their function had weakened significantly.
The liver, however, was another matter. The medications he had been taking placed strain on his already fragile liver, worsening its condition.
"If no transplant is done, he might only have five or six years left to live," Unohana silently assessed after examining his organs.
Nanatsuki turned to observe Akita and Rie's progress.
Rie led the operation on the Reishi Shell, with Akita assisting.
This wasn't Rie's first transplant. Previously, she and her teacher had secretly performed a Spiritual Pressure Core transplant on Saitō.
That surgery had been confidential—even Unohana was unaware.
Rie skillfully cut open the Reishi Shell's abdomen, exposing its internal organs.
With a smooth rotation of the scalpel, she removed the liver.
"Sensei, the Reishi Shell's liver has been removed."
"Isane, take out the recipient's liver."
Isane nodded, now much calmer. Her hands moved without hesitation as she excised Sōjun's liver.
"Excellent work," Nanatsuki nodded gently. "Now I'll take over."
Akita brought over the Reishi Shell's liver.
"The key to this operation is using Kaido to activate the new liver while adjusting its Reiatsu fluctuations. Fortunately, the Reishi Shell's Reiatsu is nearly identical to the original, so this part isn't complicated," Nanatsuki explained as he worked.
Isane and Rie watched closely, sensing their teacher's Kaido.
For Nanatsuki, this was a simple surgery. Using Kaido, he quickly connected the new liver to Sōjun's spirit body.
"The lung transplant will be similar. I'll leave that to you."
"Understood!"
Soon after, Isane and Rie successfully transplanted the Reishi Shell's lungs into Sōjun's body.
His injuries weren't limited to his liver and lungs—his arm had also been affected by Baraggan's 'Respira.'
Next, they transplanted the Reishi Shell's arm onto Sōjun.
Once the procedure was complete, Akita administered an anesthetic antidote to wake Sōjun.
"Phew—nothing went wrong... I was so nervous!" Isane patted her chest.
"To think you could handle this right after graduating—you're better than I ever was!" Rie praised.
"You both did great," Nanatsuki smiled.
"Hehe, it's thanks to your teaching, Sensei!"
Half-dazed, Sōjun overheard that his surgery had been performed by recent graduates—and immediately jolted awake.
"I'm… healed?" he checked his body in disbelief—the sensations inside were completely different.
"The surgery is complete. Try standing up and see how it feels," Nanatsuki smiled.
Sōjun tried standing. Though the anesthesia hadn't fully worn off and he was still a bit groggy, the sensation of being at death's door was completely gone.
He looked down at his hand.
The one previously corroded by Baraggan's 'Respira' and lost—was now fully restored.
"This arm is newly cultivated. It's different from your original. You'll need some training to return to your former strength," Nanatsuki explained.
To regain his abilities, Sōjun would need a rehab period.
"Thank you for giving me a second life," Sōjun said with deep gratitude. "Captain Katori, if you ever need anything, please don't hesitate to command me!"
"Go on now. Your father's waiting outside." Nanatsuki patted him on the shoulder. "Focus on your rehab."
He glanced at the Status Interface, which displayed two messages:
[Taught disciple Kotetsu Isane during transplant surgery. Reward settlement complete.]
[Taught disciple Hoshino Rie during transplant surgery. Reward settlement complete.]
These teaching missions were similar to previous experiment-based ones: as long as the disciples gained something, rewards were earned.
The rewards were dynamically calculated based on the complexity of the teaching.
This session yielded a total of 20,000 General Ability EXP.
Outside the medical chamber, Kuchiki Ginrei was pacing nervously.
"Captain Katori!" Ginrei approached quickly.
"Rest assured, Kuchiki-dono. The surgery was a success." Nanatsuki stepped aside—Sōjun stood behind him.
Seeing his son healthy, Ginrei finally relaxed.
"Thank you, Captain Katori. If you ever require assistance, you need only ask," Ginrei said solemnly.
"You father and son really are alike. Sōjun said the same thing the moment he woke up," Unohana smiled.
"It's only right. The Kuchiki Clan will never forget what Captain Katori has done for Sōjun," Ginrei nodded respectfully.
"Sōjun still has rehab ahead before he can fully recover," Nanatsuki added gently.
This transplant had brought Nanatsuki great benefit as well.
The Kuchiki Clan's goodwill could prove useful in the future.
And with Ginrei pushing for the policy revision, other Shinigami suffering from physical disabilities could now receive help.
Most importantly, the authority to create Reishi Shells now rested with the Department of Technological Development.
That meant additional funding could be earned through organ production.
Katori-ryu Dōjō
At the Katori-ryu Dojo, Nelliel was sparring with Azashiro Sōya.
Her Reiatsu was far superior to Sōya's, so she suppressed it deliberately to match his level.
Batsu'unsai sat leisurely on a swing beneath a red maple tree, watching them as she offered guidance.
Most of Nanatsuki Katori's disciples had already graduated and taken up posts across various divisions.
Komamura Sajin had joined Squad Seven, while Shiba Isshin and Yadōmaru Lisa had joined Squad Ten.
Nanatsuki's students had a tendency to prefer divisions without current captains.
Isshin was confident in his abilities and aimed to become Squad Ten's new captain.
Lisa chose Squad Ten because she felt Komamura's strength was overwhelming and not worth competing with. Other vacant squads already had fellow disciples in them, making Squad Ten her best shot at eventually becoming captain.
Now, the only regulars at the dōjō were Sōya and Nelliel.
Golden light glimmered at Sōya's fingertips—a light cord shot toward Nelliel like a whip.
Nelliel sidestepped the attack gracefully. As the cord shot past her, Sōya swiftly raised his hand, and the cord reversed direction midair, attempting to ensnare her.
Thump—Nelliel's figure vanished in an instant.
In the next moment, she reappeared behind Sōya, blade drawn.
"So fast!" Sōya exclaimed, feeling the blade at his throat. "I still can't get used to the speed of Sonído!"
"Switching from Shunpo Iaido to Sonído Iaido may be faster, but spatial movement speed doesn't translate to striking power," Batsu'unsai commented with a soft shake of her head.
Since Nelliel wasn't a Shinigami, she couldn't use Shunpo or Kidō, making her training path different from the others.
Batsu'unsai, with time on her hands, had decided to help adapt Katori-ryu sword techniques so that Nelliel could use them effectively.
"Someone's coming," Batsu'unsai murmured, her brows twitching slightly.
"Then I'll head inside."
Nelliel sheathed her sword and retreated. As a Hollow, her presence might cause trouble if outsiders saw her, so she usually stayed indoors when guests arrived.
"It's Kakyō… but there's an unfamiliar Reiatsu with her."
Batsu'unsai had sensed who was approaching the dōjō.
"Didn't Kakyō say she went back to her hometown?" Sōya asked in surprise.
Moments later, Kakyō arrived with someone in tow.
"Shishō!" she greeted warmly.
"And this is…?"
Batsu'unsai looked at the man beside her—he was blind.
Suddenly, a past conversation resurfaced in her memory.
"He's that close friend you mentioned back in your hometown, isn't he?" Batsu'unsai asked with a smile.
"Yes, this is Tōsen Kaname," Kakyō nodded. "I brought him here because he also wishes to become your student and train at the dōjō."
"Lady Katori," Tōsen bowed respectfully, "I wish to train under you at the Katori-ryu Dojo."
During the journey, Kakyō had already explained the dynamics of the dōjō to him, so he knew that this woman was none other than the original captain—Katori Batsu'unsai.
"Oh? A prospective disciple?" Batsu'unsai chuckled lightly. "Then you'll have to wait a while. Nanatsuki has some business today and will be back a little late."
She didn't say much else, simply instructing Tōsen to wait for Nanatsuki's return.
After all, Nanatsuki had proven time and again that his eye for choosing disciples was extraordinary—Batsu'unsai had long since stopped interfering in his decisions.