Nanatsuki continuously repeated the process of debridement, suturing, and casting Kaidō.
When Kuchiki Sōjun was struck by Respira, he had used Chiecho to scrape away the flesh contaminated by the attack.
But under such urgency, that operation could never have been done precisely.
Due to Chiecho's blow, his lungs and liver had sustained severe damage.
Nanatsuki had to piece those fragments together bit by bit.
It was an extremely complicated undertaking.
Threads of Reishi, condensed through Kaidō, were used to stitch the fragments together. These spiritual threads weren't just sutures—they were part of Kaidō itself.
As he stitched, the pieces began to heal and regenerate.
This was top-level Kaidō.
Inside the infirmary tent, all the medical Shinigami were watching Nanatsuki's hands intently. Even their breathing had slowed, fearful of disturbing him.
—
Several hours later.
Nanatsuki finally finished repairing the lungs and liver.
"It really worked!"
"Incredible! Those pieces were practically meat paste, and Katori-sensei still managed to put them back together!"
"His Kaido Thread of Healing technique is flawless... to cast it so many times without his hands trembling even once—his control is probably on par with Captain Unohana!"
"His Reiatsu is incredibly deep. Otherwise, there's no way he could have sustained this long."
"The rumors were true. Katori-sensei is already at captain-level strength."
The medical Shinigami all looked at him with awe.
The team leader of the medical unit, Shijima Suzu, a seated officer of the 4th Division, also breathed a sigh of relief.
Thank goodness Nanatsuki had been there. Had it fallen to her to handle this surgery, she had no confidence she could have managed such severe wounds.
"Katori-sensei's medical skill and Kaidō have only gotten stronger. I wouldn't have been able to treat this at all," Suzu said with admiration.
"This will only preserve his life. His lungs and liver won't return to how they were before," Nanatsuki shook his head. "A lot of tissue is missing. All I could do was stitch together the fragments I could find."
Kuchiki Sōjun had used his Zanpakutō Chiecho to carve out the flesh corrupted by Respira, so it was inevitable that parts of the organs were lost.
Kaido could rejoin what was broken, but it couldn't create something out of nothing.
"Then… how much of the lung and liver function will remain?" Suzu asked.
"There's too much missing. It's hard to say yet—it depends on his recovery," Nanatsuki replied after some thought.
From what he could tell, the damage was so extensive that it would likely have a massive impact on both Sōjun's strength and lifespan.
In truth, there was a way to fully restore Kuchiki Sōjun—by manufacturing a Reishi Shell for him and replacing the damaged organs.
Fortunately, his injuries hadn't touched the Spiritual Pressure Core, so there was no concern about spiritual integrity.
His Reishi Shell wouldn't even need long cultivation; it could be quickly used to replace his organs.
However, producing Reishi Shells was currently banned by Central 46. There was no way Nanatsuki could openly propose such a plan.
'Kuchiki Ginrei... what would you choose?'
Nanatsuki wondered silently.
The Kuchiki family had always adhered strictly to the rules—they were nobles who would not break the law.
Kuchiki Ginrei was the same.
When he trained Kuchiki Sōjun, he often emphasized the importance of the family's discipline and tradition.
In his current condition, Sōjun would not only be unable to become a captain in the future—he might not even retain vice-captain-level strength.
Nanatsuki was genuinely curious: if the option to violate a taboo could save Sōjun, what choice would Ginrei make?
After finishing with the lungs and liver, Nanatsuki began treating the damage to the heart.
Those injuries had been caused by internal Reishi surges and would recover naturally after rest. They wouldn't impact function long-term.
—
Half an hour later, Nanatsuki completed the entire procedure and left the room.
Outside, the two 6th Division seated officers had been waiting for a long time.
Ashido had already departed—now that the battle was over, there were many post-battle duties to handle, such as cleaning the battlefield and casualty assessments.
When the two seated officers saw Nanatsuki, they immediately rushed over.
"Katori-sama, how is the Vice-Captain?"
"The surgery was very successful. Sōjun's life has been saved."
Just as they were about to breathe a sigh of relief, Nanatsuki added:
"But... his lung and liver function are compromised. It may affect his strength."
"How badly...?" One officer's expression changed slightly.
"Hard to say. It depends on his recovery," Nanatsuki replied, leaving it open-ended.
The two looked at each other in silent concern.
"Sensei!"
Nanatsuki turned his head and saw Shihōin Yoruichi in the medical tent as well.
The wounded members of the Onmitsukidō were also being treated here.
"That's... Kuchiki Sōjun's Reiatsu, isn't it?"
Yoruichi glanced at the room behind him and asked with a frown, "That fluctuation… was he badly injured?"
After carefully sensing it, she found his Reiatsu flickering like a candle in the wind—clearly gravely wounded.
"He ran into the King of Hueco Mundo—Baraggan—and was severely wounded," Nanatsuki said. "I just finished operating on him."
"He actually crossed paths with the King..." Yoruichi said. "I heard you killed him."
"Yes, I rushed over as soon as I got Sōjun's distress call," Nanatsuki nodded.
Though he had responded quickly, the gap in strength between Sōjun and Baraggan was too great—he hadn't held out long.
At that moment, Ashido, who had received a report from his subordinates, arrived.
As the Expeditionary Commander, and since Sōjun had been sent in as support, it was his duty to check on his condition.
"Katori-kun slaying the King of Hueco Mundo... the Hollow Realm will probably be quiet for quite some time."
Ashido sighed. "The Expeditionary Force will suffer far fewer casualties because of this."
The peace he spoke of applied only to the Shinigami.
With Baraggan's fall, a power vacuum would open in Las Noches.
The stronger Menos would begin infighting, competing for the throne.
With their focus on internal conflict, they would have no time to attack the Expeditionary Force.
"But the Shinigami stationed in the World of the Living are going to be busy," Nanatsuki said.
With Las Noches in disarray, some Hollows would undoubtedly slip into the Living World and cause chaos.
"Every gain has its cost," Ashido nodded. "Until they choose a new king, the stationed forces in the Living World will have to endure the brunt."
"What about Vice-Captain Kuchiki's injuries?" Ashido asked.
"The operation went well. He'll live—but there may be aftereffects," Nanatsuki replied.
"That's unfortunate... he's still so young," Ashido sighed. "But Katori-kun's medical skill is truly remarkable. That 4th Division officer said earlier that saving Sōjun was almost impossible."
Now, Ashido had a much deeper appreciation for Katori Nanatsuki's medical and Kaidō expertise.
Before Nanatsuki arrived, Officer Shijima had already pronounced Sōjun's condition terminal.
It was only after repeated begging from the two 6th Division officers that she reluctantly agreed to try.
—
From there, Nanatsuki stayed behind at the medical station to help treat other severely injured Shinigami.
—
A few days later, the somber-faced Kuchiki Ginrei waited before the Senkaimon.
He had received advance notice of the 6th Division's return and was here to greet them.
As the gate opened, the Shinigami of the 6th Division began to emerge.
"Captain Kuchiki!"
Some still called him by his old title, despite his retirement.
Ginrei gave a light nod, his eyes fixed on the gate.
Kuchiki Sōjun, pale-faced, sat in a wooden wheelchair.
"Father... I'm sorry..." cough cough cough— Sōjun could only say a few words before violently coughing up blood, staining the handkerchief and growing even paler.
"Say no more. Just rest."
Even though Ginrei had been mentally prepared, his heart still felt heavy.
"Let's send Sōjun to the 4th Division for proper care first."
Nanatsuki stepped out of the gate. "The expedition camp's conditions are limited—we couldn't fully stabilize his spiritual body there."
The Shinigami pushing the wheelchair looked to Ginrei for confirmation.
"Listen to Katori-kun."
Ginrei nodded, and the Shinigami promptly pushed Sōjun toward the 4th Division.
The academy students who had accompanied Nanatsuki also emerged.
"You guys return to the Academy on your own. I have something to discuss with Lord Kuchiki."
Under Nanatsuki's signal, the students went to submit their mission reports.
All of them had completed their assignments during the battle and passed the early graduation exam—they only needed to report back to officially graduate.
Nanatsuki accompanied Ginrei back to the Kuchiki estate.
—
The mansion was a traditional Japanese courtyard with a cherry blossom tea garden.
After passing through the gate and along the path, they sat down at the tea terrace.
"Please, sit." Ginrei prepared tea with graceful movements.
A short while later, a cup of hot tea was placed before Nanatsuki.
"Please enjoy."
"Excellent tea," Nanatsuki commented after a sip.
"It's this year's first flush. If you like it, I'll have some sent to your dojo," Ginrei said as he refilled the cup. Then, he got to the point:
"I've already consulted Captain Unohana and Captain Hikifune. They confirmed Sōjun's injuries are extremely severe. What is the treatment plan you mentioned?"
Nanatsuki had already briefed Ginrei about Sōjun's situation through the Denreishinki—but not the treatment plan.
He didn't want to mention anything sensitive via a device that the Intelligence Division might monitor.
Both Unohana and Hikifune had been consulted—neither could handle such a wound.
Now, all hope rested on Nanatsuki.
"This is something Captain Hikifune could do herself. The reason she hasn't suggested it..."
Nanatsuki sipped his tea.
"...is probably because of Central 46's ban."
His treatment plan was to create a Reishi Shell to replace Sōjun's damaged organs.
Captain Hikifune also knew how to create Reishi Shells. She had likely thought of the same plan—but remained silent due to the prohibition.
"Central 46's ban?" Ginrei frowned. "Please explain, Katori-kun."
"Surely you remember the Reishi Shell incident years ago. My plan is to create a shell for Sōjun and transplant replacement organs," Nanatsuki explained.
"Reishi Shell organ replacement..."
Ginrei's heart sank.
Creating Reishi Shells had indeed been explicitly banned by Central 46.
They feared the shells might one day replace real Shinigami without anyone realizing it.
"I'm confident in the plan—it poses no real risk to Sōjun," Nanatsuki said.
"But it would mean defying Central 46's edict." Ginrei replied gravely. "The Kuchiki Clan cannot take the lead in breaking the law. Otherwise, what order would remain in Soul Society?"
As one of the Four Great Noble Houses, the Kuchiki Clan didn't fear Central 46.
But they could not be the first to defy them either.
Still, could he really just let Sōjun waste away like this?
Ginrei's thoughts were in turmoil.
"I'm bound by the ban as well," Nanatsuki said quietly. "I only brought this up because I was once Sōjun's instructor. If you're unwilling, I won't go against the rules just for his sake."
Ginrei quietly poured more tea while deep in thought.
'The Kuchiki... truly are stubborn.'
Nanatsuki muttered inwardly.
Even if no one would ever know, Ginrei would still uphold the rules.
The Kuchiki family held themselves to the standard of nobles—openly and in secret.
After a long pause, Ginrei finally said:
"Surely Sōjun isn't the only Shinigami with missing limbs or organs. I will attempt to petition Central 46 to lift part of the Reishi Shell ban."
The treatment was right in front of him—and Ginrei still refused to give up.
If the ban could be lifted, then it wouldn't be breaking the rules at all.
"Indeed. If Reishi Shell technology can be used to heal wounded Shinigami, it would be a great blessing. I'll await your word, Head of the Kuchiki Clan," Nanatsuki nodded.
He had expected this response.
Nanatsuki also wanted the ban on Reishi Shells to be eased.
Based on years of research, he knew that Reishi Shells were perfect for healing lost limbs or organs.
Such body parts didn't require a Spiritual Pressure Core.
They weren't responsible for channeling Reiatsu—so even short-cultivated shells could be used as replacements.
Unawakened Reishi Shells had no consciousness. In Nanatsuki's view, they were no different from regular body parts.
Using them to replace organs or limbs posed no ethical burden.
Banning the entire field just because of fear was short-sighted.
Nanatsuki was also thinking ahead—preparing to take over the 12th Division.
The 12th Division was the only organization in the Court Guard Squads that could create Reishi Shells.
If the bans could be partially lifted and Reishi Shell tech permitted in healing, the 12th Division would receive more research funding.
And with proper funding, he could realize his vision of transforming the 12th Division into a true Bureau of Technology.