12th Division, formerly Hikifune Kirio's lab.
"Captain, this is our latest research project in the lab."
Urahara Kisuke's eye bags had grown even darker.
Ever since they acquired a large amount of Hell Reishi from the Tsunayashiro family, he'd become very interested and had been studying it non-stop.
Nanatsuki was now officially the Captain of the 12th Division and was preparing to take over what Hikifune Kirio had left behind.
"These things…" Nanatsuki looked at the various flasks and bottles. Inside, the Hell Reishi had condensed into recognizable symbols. "Aren't these Kidō formula?"
These symbols were commonly used in Reishi barriers and sealing arrays, but here they were composed of Hell Reishi.
"We're experimenting with applying Hell Reishi." Urahara explained, "Captain, you were a firsthand witness of the Execution Captain's return, so you probably know that even after becoming a denizen of Hell, he could still use Kidō, right?"
"That's true. During his fight with Commander Yamamoto, he cast Kidō." Nanatsuki nodded.
"We collected the Reishi traces from that scene. The lingering Reishi the Execution Captain left behind was tainted with the aura of Hell—it was Hell Reishi. So we believe Hell Reishi shares some characteristics with regular Reishi," said Urahara. "That's why we're trying to use Hell Reishi to cast Kidō spells. If successful, it could allow Shinigami to remain in Hell for longer periods."
Hell's environment is extremely hostile to Shinigami—their abilities are heavily suppressed.
Even casting Kidō in Hell is significantly weaker than in the other three realms.
If Shinigami could use Hell Reishi, it would be a huge boon for exploring Hell.
"This direction is worth further study." Nanatsuki nodded, signaling to keep this project active.
The Lord of Hell was clearly eyeing the Three Realms. The Shinigami needed to be prepared.
Urahara and several researchers continued to lead Nanatsuki onward.
"Captain, this is my project."
A skin-and-bones Shinigami stepped forward eagerly. "Captain must've tasted the food Hikifune-taichō made using the Temporary Soul technique, right? My project was inspired by that!"
"Hikifune-taichō could inject Reiatsu into food using the Temporary Soul technique—but that was tied to her Zanpakutō. So, if we want to boost Reiatsu in the same way, we need a new method."
Inside a culture flask were tiny blue glowing Reishi beads, resembling luminescent caviar.
"Oh? Are these Reishi clusters made using the Temporary Soul technique?" Nanatsuki asked, intrigued.
Hikifune Kirio's Temporary Soul technique had endless potential and many future research directions.
It was thanks to that invention that she had been promoted to the Royal Guard.
If these Reishi clusters were a product of that technique, they might be another revolutionary breakthrough.
"Well… not quite. These clusters were extracted from my spiritual body!" The skeletal Shinigami rolled up his sleeve, revealing arms riddled with pinholes. "These clusters can also boost Reiatsu!"
"..." Nanatsuki glanced at the man's emaciated frame, frowning. "No rejection reactions?"
Such a crude extraction process would cause the Reishi to carry the host's traits. Injecting them into another soul would be no different from forcibly transferring Reiatsu.
"There's still no solution to the rejection issue…" the man said anxiously. "Captain, please give me more time! A year… no, six months, I swear I can fix it!"
"Scrap the project." Nanatsuki, now sure this was just a budget scam, moved on.
The skeletal man looked utterly crushed.
Hikifune Kirio had run the lab with a loose grip. Aside from her own projects, researchers were left to pursue what they wanted freely.
As a result, not all the research here was useful.
Now, Nanatsuki needed to start cutting the dead weight.
The group arrived at a culture tank filled with nutrient fluid.
Inside floated a spiritual body. Nanatsuki sensed it—it was a corpse.
Normally, a spiritual body like this would dissolve into Reishi over time. The only reason it remained intact was due to the special nutrients preserving it.
"Captain, this is my project," said a green-haired Shinigami named Yosha.
"This project was left behind by Hikifune-taichō. Now I'm in charge."
"She proposed a concept called 'Artificial Soul'—inserting a Temporary Soul into a spiritual body."
"Hikifune and I have discussed Artificial Souls before," Nanatsuki said with a nod. "But how does this relate to the corpse?"
"Before she left, we developed this—" Yosha took out a smooth, round orb. "This is the product: the Gikongan (Artificial Soul Pill). It was made using Reishi extracted from this corpse."
"Gikongan…" Nanatsuki took the orb, recognizing the name.
Gikongan could forcibly eject a soul from its body—and each pill was also a self-aware spirit.
In the future, Shinigami would use artificial bodies (Gigai) to operate in the human world.
The Gikongan would help Shinigami leave their Gigai and even remotely control them.
However, it seemed Nanatsuki's past interactions with Hikifune Kirio had subtly altered the research timeline.
Originally, Gikongan was developed after she left the 12th Division—but Nanatsuki often came to share cooking tips and Reishi knowledge with her, influencing her progress.
"If the Gikongan can be used on souls that refuse to leave their bodies after death, it can forcibly separate them. Plus, since the Gikongan has self-awareness, it can even inhabit a human body to help us communicate with people without Reishi sensitivity," Yosha continued.
Humans without Reishi sensitivity couldn't perceive souls or Shinigami.
Since Gigai hadn't been invented yet, Yosha hadn't realized Gikongan would have future uses beyond this.
"Impressive," Nanatsuki nodded. "But if we could give Shinigami physical bodies made of Reishi Particles, it would make interaction with humans much easier."
"You mean something like the Flesh Puppet?" Urahara scratched his cheek. "That Divine Armament is ridiculously expensive to make..."
Nanatsuki had once found a single Flesh Puppet among the Tsunayashiro family's treasures. It served the same function as a Gigai, giving Shinigami a temporary body. But as a Divine Armament, it was far too costly to mass-produce.
"Then find a way. If we could invent Temporary Souls, making a more affordable vessel shouldn't be a problem." Nanatsuki clapped Urahara's shoulder. "Kisuke, I'm putting you and Yosha-kun in charge of this project. If you pull it off, it'll benefit all of Soul Society."
"With such trust, I'll give it my all!" Yosha was overwhelmed with emotion.
Urahara, on the other hand, remained calm. He mostly just felt… extremely pressed for time.
The researchers continued showcasing their work.
Nanatsuki noticed a set of oddly shaped swords—he recognized them.
"Captain, these are the Bakkōtō we confiscated from the Kasumioji lab," Saekae explained.
She was the only female researcher in the lab, with long wavy purple hair, a lovely face, but a tired aura.
"Weren't those Bakkōtō all destroyed?" Nanatsuki asked, puzzled.
He'd been directly involved in the incident and had followed up on its conclusion.
The public report claimed all Kasumioji-manufactured Bakkōtō were destroyed.
Clearly, that wasn't entirely true.
"These are the best of the batch, far stronger than many Shinigami's Zanpakutō," Urahara said with a grin. "The Central 46 couldn't bear to part with them. They ordered Hikifune to study ways to eliminate the side effects."
"And since they were funding the project, she took it on," Saekae added. "Progress is slow, though—we still need a host's Reiatsu to feed the core."
"Looks like the 'big shots' are still hungry for power." Nanatsuki stroked his chin. "Well, if Central 46 is footing the bill, we'll keep it."
Anything that could be researched using their money wasn't worth canceling.
And if the results were promising, as captain, Nanatsuki would ultimately control how the weapons were used.
"Captain, I'd like to show you my 'Memory Shift Device' project," said a bald Shinigami, holding a square box. "When Shinigami operate in the World of the Living, they inevitably draw human attention. This device erases those memories."
"Oh? A memory-erasing tool?"
Nanatsuki took the device. In the modern age, such a tool would be indispensable. Shinigami stationed in the Living World would each need one.
Information spreads rapidly in modern society, and once something goes viral, it's hard to contain. With a memory-wipe tool, any affected humans could be cleanly handled.
"Yes. It emits a Reishi wave that affects the human brain, erasing memories," the bald man confirmed.
"Has it been completed yet?" Nanatsuki asked.
"Not quite… right now it can only wipe large memory chunks, which has major side effects. It still needs refinement," he replied seriously. "Please give me a bit more time. I'm confident I can perfect it!"
"The potential is huge. This project stays." Nanatsuki nodded.
"Captain! Check out my project—I'm researching the secret of Zanpakutō already released... So here's my theory…"
"Wrong direction. Scrap it."
"Captain, my project is to restore Temporary Souls into standard Reishi…"
"I can do that with a Hadō spell. Scrap it."
"Captain—"
"Scrap it."
After leaving the lab, Nanatsuki brought Urahara to the office.
"You seem to have strong opinions about the lab," Urahara said, munching on a pastry. "Mmm… better than the ones from Ichibanfang."
"There just aren't enough capable people…" Nanatsuki sighed. "Even Hikifune-san was the best of a weak batch."
After touring the lab, he had cut half the ongoing projects.
There was no other choice—these researchers were all self-taught.
To put it bluntly—they were amateurs.
Without formal training, their results depended entirely on talent.
"We need to establish a researcher training system ASAP," Nanatsuki said. "Kisuke, I'll leave that to you."
"What?! I already have way too much on my plate! Can't we give it to Saekae-san or Yosha-kun?" Urahara groaned.
"This is too important for the 12th Division's future. I trust only you with it." Nanatsuki smiled.
"Thanks… but I'm seriously swamped!" Urahara collapsed into a chair. "Maybe you could help me find assistants."
"Hm… I might just know two researchers we can use."
He suddenly recalled two talented individuals:
Kurotsuchi Mayuri and Akon.
In the original timeline, Urahara would lead the 12th Division, and Mayuri would become his successor.
Akon would serve as Mayuri's vice-captain.
Right now, both were probably still locked up in the 2nd Division's prison: the Maggot's Nest.
They'd been thrown in for violating regulations.
Nanatsuki had already been looking into them. He'd even asked Yoruichi about their whereabouts.
Mayuri had been imprisoned for studying Quincies.
During the Quincy extermination campaign in the Living World, many Quincy corpses were left behind.
Mayuri had secretly snuck over, hoping to bring the bodies back to Soul Society for research.
But his actions were discovered by the Onmitsukidō.
Studying Quincies was strictly forbidden. He'd been locked in the Maggot's Nest ever since.
As for Akon, he used to serve a minor noble house. When that house was caught in a scandal, he was implicated and also locked away in the Maggot's Nest.