(T/N: This is chapter 2 out of 6!)
"You know how to make the Spiritual Body Growth Serum now, Sōsuke. From now on, these Reishi Shells need an injection every three days. You can teach the preparation process to Rie—if she has time, she can help manage it."
Katori Nanatsuki was planning to continue cultivating the Reishi Shells brought back from Miyamoto Tetsuya's lab using the serum.
These shells, having been exposed to the Spiritual Body Growth Serum long-term, had accumulated trace amounts of Hollow Reishi inside—useful for Hollowfication experiments.
But Nanatsuki and Aizen Sōsuke had already confirmed that conventional Hollowfication methods didn't work on Shinigami Reishi Shells. Nanatsuki now intended to add a new variable—fragments of the Soul King—to proceed with the experiments.
"Alright." Aizen nodded. The serum preparation process was easy for him—one glance was enough to memorize it.
At that moment, the lab door opened. Hoshino Rie stepped in.
She gasped upon seeing the abundance of shells and equipment.
"Sensei, I brought the list." Hoshino Rie waved the sheet of handwritten notes in her hand.
"Thanks for the hard work, Rie." Nanatsuki took the list and began reviewing it.
"It wasn't much. I'm just happy I could help!" she said. "But this kind of injury you're focusing on—the prognosis is grim. The Quincy Purge happened years ago. Not many survived."
Aizen peeked over curiously. It was a list of injured Shinigami.
Ever since returning from the World of the Living, the first thing Nanatsuki did was ask Hoshino Rie to search the 4th Division's records for patients with damaged Spiritual Pressure Cores.
The large-scale battle in the Human World—the Quincy Purge War—had inflicted significant losses on the Gotei 13. Nanatsuki had helped the 4th Division at the time and knew that many severely injured had Spiritual Pressure Core damage, just like Katori Batsu'unsai, and were considered incurable.
Nanatsuki glanced at the list. There were nine Shinigami with damaged cores.
After follow-up investigations, six had already died due to Spiritual Pressure Core failure and subsequent spiritual collapse.
Such was the fate of Shinigami whose core was beyond repair.
Their Reishi Shells and core durability were far inferior to Katori Batsu'unsai's, making their decline far more rapid. In just a few years, they were already past saving.
"Only three are left," Nanatsuki sighed in relief. As long as someone survived, he still had candidates to work with. Otherwise, he'd have no subjects with this kind of injury.
Before, there had been no viable treatment. Now, with the serum, it was possible to cultivate a Reishi Shell with spiritual pressure matching a regular Shinigami. The idea was to replace the damaged core and heal the injury.
Though untested, Nanatsuki planned to practice on the three survivors before attempting the procedure on Katori Batsu'unsai.
He wasn't worried they'd refuse.
If they did, death awaited them anyway.
"These three Shinigami—they've already been relieved from duty due to illness, right? Can we still contact them?" Nanatsuki asked.
"It shouldn't be a problem. They still visit the 4th Division for medicine. We even followed up on them last month. I asked the Shinigami in charge—each still lives in their Division quarters," Hoshino Rie replied.
Nanatsuki intended to visit them in person to explain the treatment plan.
Together, they visited the 3rd Division under the pretense of follow-up care.
He had already seen the other two previously. Both were from the 11th Division.
After examining them, he found their condition grim. They were in deep comas, and their spiritual bodies wouldn't hold out for long.
Even starting from scratch with the serum, it would take 2–3 years to grow a replacement shell to the level of a Division soldier.
Nanatsuki concluded that their cores were already at their limits—collapse was imminent.
Their situation was even worse than Batsu'unsai's. At least she had Nanatsuki, whose spiritual particles were compatible, allowing him to prolong her life using Spirit-Converging Pills.
Reluctantly, Nanatsuki turned to the final surviving patient.
This last one was a former seated officer of the 3rd Division—stronger than the average Division soldier.
The door was opened by someone he recognized: Saitō Akane.
"I'm Hoshino Rie from the 4th Division. I'm here to follow up on Saitō Rei's condition," she said. "This is my teacher. He's more experienced in dealing with Spiritual Pressure Core issues, so I brought him along."
"Katori-san?" Saitō Akane looked surprised to see Nanatsuki.
"Miss Saitō. We meet again," Nanatsuki smiled.
As it turned out, the patient was Akane's twin sister: Saitō Rei.
Saitō Rei had been the 6th Seat of the 3rd Division. Her core injury during the war had weakened her strength and forced her to step down. Her replacement was none other than Nanatsuki's student, Azashiro Kana.
"Please, come in." Akane seemed genuinely hopeful. Though her sister's condition was currently under control thanks to medication, she feared it would deteriorate over time.
She led them into Rei's room. The twins looked nearly identical.
Rei's condition seemed stable. With her background as a seated officer, her injuries weren't as severe as those who had already passed. Thanks to medication and Kaido treatment, there were no visible symptoms.
"Sis, who are they…?" Rei asked. She recognized Nanatsuki. "Aren't you the instructor from the Spiritual Arts Academy?"
"I came to assess your condition. We've recently made a breakthrough in treating Spiritual Pressure Core injuries. There's a chance yours could be healed," he said frankly.
"I just got meds from Captain Unohana yesterday… and I didn't hear anything about that," Rei said, clearly stunned.
In her view, Unohana Retsu had the highest Kaido mastery. If even she had no solution, how could Nanatsuki claim otherwise?
"This treatment doesn't rely solely on Kaido," Nanatsuki shook his head. "It involves a classified method. I'll only explain it if you both swear to keep it secret."
Saitō Akane, having interacted with Nanatsuki before, trusted his sincerity. She immediately said, "If there's even a chance to heal Rei, we'll keep it secret. As long as it doesn't mean betraying the Soul Society, we'll do anything."
Akane had previously inquired with Unohana. The prognosis for Shinigami with the same injury was universally poor—they didn't last more than a few years before collapse.
Though Rei had a stronger spirit body, it only meant she'd survive a little longer.
There was no cure within the 4th Division.
Nanatsuki's treatment was a lifeline.
"Don't get too excited. This is still experimental—but I'm confident I can cure Miss Rei," he said seriously.
"My condition is stable for now, but I won't hold out forever," Rei admitted. "If you think it can work, I'm willing to take the risk."
She had spent time recovering in the 4th Division, and she trusted Nanatsuki's Kaido expertise.
"Since you're both willing, I won't hide it anymore. You've heard of the Reishi Shell incidents lately, right?" Nanatsuki asked.
They nodded.
"Of course. Just yesterday, Commander Yamamoto ordered all Divisions to investigate the shells hiding in Seireitei," Akane replied. "I heard the mastermind, Miyamoto Tetsuya, was eliminated by you. Is your treatment plan related?"
"It is," Nanatsuki said. "I plan to cultivate a shell using Miss Rei's spiritual particles. The cultivated shell will share her origin. By transplanting the shell's Spiritual Pressure Core into her, we can heal the injury."
The concept was originally proposed by Tenjirō Kirinji.
Back then, the technology wasn't advanced enough to cultivate a compatible core for someone like Katori Batsu'unsai.
But now, with the serum, the method was viable again.
"You need to create a Reishi Shell of me… that does sound promising," Rei admitted. She knew it would violate the Central 46's ban on shell production, but survival trumped law.
"Then I'll leave it to you, Katori-san," she said solemnly.
Even if it meant breaking the law—she wanted to live.
"Don't worry. I'm confident this will succeed," Nanatsuki said with a smile.
After reviewing Miyamoto Tetsuya's notes, he believed producing a compatible core for Rei wouldn't be difficult.
He pulled out a syringe from his Reishi Pocket and took a blood sample from Rei.
"To cultivate a suitable core, we'll need one to three years. Please take care of your health until then," he told her.
"No problem—I'll make sure she does," Akane replied, hugging her sister.
Nanatsuki and Hoshino Rie left the 3rd Division. Azashiro Kana was apparently out on assignment—they didn't run into her.
Back in the lab, Nanatsuki began culturing the shell using Rei's blood.
The sample was enough to cultivate multiple shells. To be safe, he started several simultaneously.
If something went wrong, Rei's condition might not hold out long enough for a second attempt.
Hoshino Rie gazed at the rice-grain-sized embryos floating in the nutrient chambers. "This tech can heal or cause chaos. After all the shell incidents lately, even our 4th Division received internal audit orders."
After Nanatsuki eliminated Miyamoto, Commander Yamamoto had ordered a full purge of remaining shell entities to prevent their resurgence.
Aizen Sōsuke remarked casually, "Technology, like power, isn't good or evil—it depends on who wields it."
Before the Academy semester began, Nanatsuki still had one more thing to handle.
So much had happened lately that he nearly forgot something important.
While traveling with Commander Yamamoto, Nanatsuki had promised Sajin Komamura he'd deal with the werewolf clan's hunt for him.
Komamura had been hiding at the dojo since Nanatsuki brought him back. The werewolves couldn't find him.
But Komamura couldn't stay hidden forever—Nanatsuki had to eliminate the threat.
He and Komamura arrived at Inuyama.
As soon as they entered the area, werewolves were everywhere.
All the residents here were werewolves.
There was even a marketplace—staffed entirely by werewolves.
They weren't beasts—they had needs like everyone else.
"Sensei, the tangerine wine here is amazing," Komamura said, stopping at a liquor shop and pulling out a coin purse embroidered with a dog's head.
During his time at the dojo, Komamura had earned some money by doing homework for Shiba Isshin.
Shiba Isshin, a valued junior of the Shiba Clan, was still in training and had mountains of homework every day.
By helping him with Kidō theory and Shinigami basics, Komamura learned the material and earned some pocket money—he was happy to do it.
"It's quite good," Nanatsuki agreed after a sip, smiling. "You bought the wine you sold in Suzuka District from here, right?"
"Yep. This shop's tangerine wine is famous around Inuyama," Komamura replied, licking his lips. He only had enough for one jug.
"Moderation—we still have work to do." Nanatsuki tossed the gourd back to him.
As they talked, several armored werewolves had already surrounded them.