(T/N: Third Chapter!)
Hikifune Kirio stood inside the cell, examining a mindless Reishi Shell.
Its brain had already turned to mush, yet the Reiatsu within still preserved its basic life functions.
It hadn't died—at least not immediately.
After a brief examination, Kirio stepped over to the adjacent cell to inspect the other detained Reishi Shell.
"This kind of condition… it's as if a spiritual particle formula was implanted in the brain to deliberately destroy it—probably to prevent information leakage," she said, turning to the seated officer of Squad 9. "What intel were you interrogating him for when this happened?"
The tall, thin Shinigami produced an interrogation log. "It was when we were questioning him about the 'God of Soulsoil.'"
"God of Soulsoil?" Kirio found the name oddly familiar and furrowed her brow.
The captains were all aware that Genryūsai Shigekuni Yamamoto and the others had encountered the Gate of Hell during their study abroad journey. That gate was believed to have been opened by followers of the so-called 'God of the Netherworld.'
They suspected that these "gods" popping up over the last two years might just be aliases created by Hell's Will.
Kirio had her assistant retrieve a set of Reishi instruments and began scanning the particle distribution in the Reishi Shell's brain.
"There's definitely something inside the brain," she said, eyes fixed on the monitor. "We won't be able to get any answers out of him like this. The moment he tries to recall something important, the spiritual particle formula activates. Let's see if we can remove it with cranial surgery."
She turned to Katori Nanatsuki. "Katori-kun, you'll be performing the surgery. I'll handle the spirit-tech formula."
Nanatsuki nodded. "No problem."
Kirio's assistant pulled a surgical kit from her Reishi Pocket and quickly converted a portion of the prison into a makeshift operating area.
A tube was connected to the Reishi Shell, linking it to an external Reiatsu source.
Kirio made adjustments to the equipment. Moments later, a stream of high-concentration Reishi began flowing into the body.
"For this instrument to output such pure Reishi… Miss Kirio, your craftsmanship truly is extraordinary," Nanatsuki remarked in awe.
"This spiritual power generator was actually inspired by your Spirit-Converging Pill," she replied with a soft chuckle. "It can sustain the function of spirit bodies. Unohana tested it and said it worked well, so Squad 4 has already reserved a few units."
Once all was ready, Nanatsuki picked up the scalpel and cleanly opened the Reishi Shell's skull.
He had studied Reishi Shells for years—this level of surgery was second nature. He didn't damage a single piece of brain tissue in the process.
Once the skull was opened, they could see an array of red spiritual particle formulas floating within.
"These Reishi… they're not normal. They're different from those of Soul Society, the World of the Living, or even Hueco Mundo," Kirio muttered, frowning.
"Miss Kirio, have you ever encountered the Gate of Hell in the World of the Living?" Nanatsuki asked. "The feeling I'm getting from this Reishi is identical to what I sensed from the Gate."
"Hell's Reishi, huh… I never paid much attention to Hell, and I rarely go to the World of the Living," she said, shaking her head. "This is my first time seeing Hell Reishi with my own eyes."
"But regardless of the formula, if it loses its Reishi supply, it becomes ineffective." Kirio pulled a silver rod, about the size of a thermometer, from her sleeve.
She pointed it at the floating red formula above the brain.
After a few seconds, the Reishi within the red formula was absorbed into the silver tube.
With its support removed, the formula quickly disintegrated.
"What is that?" Nanatsuki asked in surprise. "It absorbed the Reishi without damaging the structure."
These anti-interrogation formulas typically include a fail-safe mechanism.
If destroyed by force, the built-in countermeasure would activate and destroy the host's brain instantly.
But Kirio's tool removed the Reishi before the structure was disrupted, rendering the formula inert—even its countermeasures couldn't activate.
"This little thing is actually a byproduct of Urahara Kisuke's work on a Reishi detector. It's called the 'Spirit Siphon Needle'," Kirio explained. "Its suction was too strong to use in the detector's sampling module, but it's perfect for disabling spiritual particle formulas like this."
"If you're interested, Katori-kun, I'll give you one."
She handed over another slender silver tube.
"You're capable of performing cranial surgeries. If you encounter another Reishi Shell like this, you can remove the formula yourself."
"Thank you so much, Miss Kirio," Nanatsuki said, bowing slightly as he accepted the Spirit Siphon Needle.
"Just be aware that the needle can only store a small amount of Reishi. Once it's full, it can't absorb more," Kirio warned.
She shook the tube in her hand, and a faint red glow shimmered inside—it was the Hell-tainted Reishi she had just extracted.
After removing the formula, Nanatsuki closed the skull and activated Kaido to begin the healing process.
The operation went smoothly. The assistant injected an anti-anesthesia agent to wake the Reishi Shell.
"Thank you, Captain Kirio, and Professor Katori. We'll take it from here and extract the rest of the intel," said Vice-Captain Niino.
"Send me a copy of the interrogation results afterward," Kirio replied with a nod.
Nanatsuki accompanied Kirio back to Squad 12 to wait for the results.
Since he had helped with the surgery, it was only natural Kirio would share what she learned.
A few hours later, while discussing new dish concepts with Nanatsuki, Kirio received the report.
"Hell's Will isn't planning something small…" she muttered, her expression growing darker as she flipped through the document.
"If not for Katori-kun and Captain Yamamoto discovering the plot during their journey… Soul Society would've been in deep trouble."
Nanatsuki took the report from her and quickly located a key detail—more than just the two Reishi Shells captured by Squad 8 had infiltrated Shin'o Spiritual Arts Academy.
The captured ones had already revealed the names of several academy students.
A group of Reishi Shells had secretly blended into the academy!
The prison unit also extracted another secret.
To open the Gate of Hell, one needs the soul of an evildoer—someone burdened with grave sins during their lifetime.
These souls are usually claimed directly by the Gate of Hell while in the World of the Living.
But the souls used in the gate Nanatsuki saw during the study trip had apparently been brought into Soul Society by these academy infiltrators.
"Those students snuck the sinners' souls into Soul Society during their graduation assessments," Kirio said. "We need to investigate the entire academy."
"Thankfully, we caught two of them before enrollment. If they'd officially started, they'd be in the academy dorms instead of Rukongai. We'd have no way of identifying them," Nanatsuki added with a sigh.
Academy students are allowed to stay in the dorms indefinitely, even during holidays.
That made it impossible for patrol Shinigami in Rukongai to search for them.
This intel may have just prevented a crisis. Letting those Reishi Shells remain would've been a major threat.
"There's one more thing," Kirio continued. "All the captured Reishi Shells mention a Shinigami called 'Lord Miyamoto.'"
"I think that's the same Miyamoto Tetsuya you asked me about before, Katori-kun."
Nanatsuki had previously suspected that Saitō Furaofushi's "Sound of Hell" technique was in Miyamoto's hands.
Miyamoto had once served as Squad 12's Third Seat, participating in the "Captain Supplement Program" and was tasked with disposing of Reishi Shells.
The intel they now possessed confirmed it—these Reishi Shells were likely his creations.
"Too bad none of them know Miyamoto's whereabouts. He only contacts them one-way. Cunning bastard…" Nanatsuki scowled.
Miyamoto had prepared for the eventuality that his creations would be captured. He never revealed his location to any of them.
"Maybe we can use the Shells to lure him out," Kirio mused.
Still, she wasn't too hopeful. With someone as cautious as Miyamoto, baiting him wouldn't be easy.
A short while later, Shihoin Yoruichi arrived at Squad 12 with the Onmitsukidō.
Since only one Reishi Shell was available for interrogation, and the reliability of that intel was questionable, the prison unit had immediately contacted Squad 2 to secretly apprehend the others in the academy.
But the Onmitsukidō couldn't guarantee a capture—Reishi Shells could self-destruct at any time.
They came to Kirio to collect tranquilizer guns.
"Captain Kirio, I'm here for the tools—oh, sensei! You're here too?" Yoruichi said, surprised.
"You're heading to the academy, right? I'll go too," said Nanatsuki.
"That'd be great, sensei!" Yoruichi nodded quickly.
Having a familiar teacher on hand would make it easier to move around.
After collecting tranquilizers, Yoruichi and the Onmitsukidō headed to the academy with Nanatsuki.
"It's been years since I've returned here. I never thought the next time would be to capture juniors," Yoruichi said with a wry smile. "I don't even know what they did to warrant a secret operation from us."
She hadn't yet received the full details—she didn't know those "juniors" were actually Reishi Shells.
"This situation runs deep," Nanatsuki said. "But with your role in the Onmitsukidō, I'm sure you'll be briefed when you return."
The Onmitsukidō had excellent intel, so Nanatsuki didn't bother explaining.
Yoruichi and her team disguised themselves in academy uniforms and walked beside Nanatsuki without drawing attention.
He retrieved a student roster and identified the class and dorm assignments of the suspects.
They headed to the dorms.
"Katori-sensei!" a student from the Swordsmanship Advanced Class waved. "Are those freshmen?"
An upperclassman assumed the group following Nanatsuki were new recruits.
"Yes. Mizutani, do you have time? Could you explain the dorm rules to these freshmen?" Nanatsuki asked with a smile.
"Of course!" the student beamed.
Nanatsuki entered the dorm alone. The list had six names: two seniors and four underclassmen.
The two seniors—suspected of bringing criminal souls into Soul Society—had deliberately failed their final exams to stay longer at the academy.
He found their room and knocked.
A short-haired male student answered nervously. "Professor Katori? Is something wrong?"
"Shirata, could you do me a favor?" Nanatsuki peered past him at the two Reishi Shells inside. "The wooden swords in the training hall need replacing. I need a few hands."
"No problem!" the student replied, relieved. He had worried Katori might be unhappy with his performance.
Nanatsuki motioned to the Reishi Shells inside. "You two, come help as well."
Not wanting to arouse suspicion, the two agreed and followed.
Nanatsuki led the three toward Yoruichi and the Onmitsukidō.
"You three go help move the wooden swords. I have other business to attend to," he said.
He exchanged a glance with Yoruichi, and she quickly caught on. "Got it!"
Mizutani, who had been explaining school rules to the "freshmen," cheerfully added, "I'll help too!"
With another upperclassman present—one of their dormmates—the Reishi Shells suspected nothing and followed them out.
"I know where the storage room is, but we should let Professor Shirai Riko know before taking anything," Mizutani said.
They headed toward Shirai Riko's office.
Inside the building, seeing that few people were around, Yoruichi gave a signal.
The Onmitsukidō moved swiftly, subduing the two Reishi Shells on the spot.
"What are you doing?!" Mizutani exclaimed. She had never seen "freshmen" attack upperclassmen before.