(T/N: Second Chapter!!)
Above the World of the Living, a Senkaimon slowly emerged.
As its doors opened, Katori Nanatsuki and Shihoin Yoruichi stepped out, followed by a group of elite Onmitsukidō operatives.
The Onmitsukidō had been tasked with investigating Miyamoto Tetsuya's experimental base, and Nanatsuki had accepted Yoruichi's invitation to accompany them to the World of the Living.
Currently, Nanatsuki and Aizen's research on Hollow Reishi Shells had already made progress—they could now produce Reishi Shells with the strength of ordinary Hollows. With time, reaching Gillian-class seemed within reach.
However, progress on the Shinigami Reishi Shell front remained limited.
Thus, Nanatsuki was quite interested in the Reishi Shell techniques Miyamoto Tetsuya had mastered.
From Nanatsuki's observations, Tetsuya had already reached the point of mass-producing Reishi Shells equivalent to seated Shinigami officers.
Compared to the sealed Reishi Shell technologies of the Seireitei, Tetsuya's iterations had advanced considerably over time.
At that moment, two cloaked Onmitsukidō agents appeared before them—scouts who had arrived in advance.
"Vice-Captain," one of them began, pointing to a massive lake below, "based on intel from the Detention Corps, Miyamoto Tetsuya's base should be beneath this lake."
"Did you locate the entrance?" asked Yoruichi.
"We did. We probed the area with spiritual pressure detectors, but couldn't pick anything up. The lab must be shielded with materials like Sakkise to block Reiatsu signatures," the agent replied.
Tetsuya had built his lab beneath the lake, shrouded in materials that obscured any spiritual presence—a secrecy so thorough that for years, even active Quincy and Shinigami in the World of the Living had missed it.
"Take us to the entrance," Yoruichi ordered with a nod.
"Yes, ma'am!"
The two agents led the group to a thicket along the lakeshore. After walking several dozen meters, they reached a large boulder hidden within the brush.
According to intel, this boulder—close to the water—marked the base's entrance.
"The tunnel to the lab is beneath this stone," the agent explained.
They rolled the boulder aside, revealing an obviously man-made tunnel beneath it.
"Stay alert. Until we locate Miyamoto Tetsuya, avoid alerting anyone. He has the ability to open a Garganta—we can't let him escape," Yoruichi instructed. "You two stay here and contact me via Denreishinki if anything happens!"
"Yes!" the Onmitsukidō responded in unison.
"Master, let's head in," Yoruichi said.
Nanatsuki nodded and took the lead into the tunnel.
Perhaps due to the proximity of the lake, the passage was damp, with water pooled along the floor and droplets falling from the ceiling.
Naturally, as Shinigami, they moved without splashing—no sound echoed through the passage.
They soon arrived at a stone door made of Sakkise. Beside it was a rotating code dial etched with animal motifs.
Only the correct combination would open the sealed Sakkise door.
Thanks to the information obtained from the Detention Corps, they already had the correct pattern. One of the agents stepped forward and rotated the dial in the specified sequence.
With a crisp click, the stone door slowly opened.
Before the guards inside could see who it was, their necks were twisted by their own shadows.
Yoruichi stepped in, scanning cautiously before signaling the others to follow—it was safe.
This inner corridor was much cleaner and more refined than the one outside, with stone brick walls lining the passage.
Passing through it, they reached a spacious hall.
"This floor is the living quarters and training area. The lab is one level down—its entrance is to the right," Yoruichi whispered, gesturing to the hallway.
In the living quarters, several spiritual bodies moved about, dressed in white lab coats or white kimono.
Freshly-created Reishi Shells needed time to stabilize. They had to be taught Soul Society knowledge and trained before being deployed.
Nanatsuki used Shadow Space to conceal the group within the corner shadows and moved toward the lab entrance.
None of the spiritual bodies noticed anything unusual.
An elevator was required to reach the next level—but it was guarded, and since others frequently used it, taking down the guards might expose their intrusion.
But the Onmitsukidō was prepared.
Nanatsuki eliminated the guard with a shadow-assisted neck twist and pulled the corpse into the Shadow Space.
One operative then pulled out a pale, dough-like item and pressed it onto the dead guard's face.
Moments later, it turned into an exact replica of the guard's face.
He handed the mask to a teammate of similar height.
"You're up."
The Shinigami took the mask and wore it. The lifeless face immediately came to life, indistinguishable from the original.
"Move out," said Yoruichi.
They descended by elevator to the lab level.
The lab was filled with neat rows of glass tanks.
Inside the Reishi nutrient fluid of each tank floated developing Reishi Shells.
"Miyamoto Tetsuya... is he planning to build an army?!" Yoruichi was stunned.
Though she had seen the intel, witnessing it in person was another matter.
She didn't need to count—there were clearly hundreds here. The floor above had dozens, maybe hundreds more already active.
The number of Reishi Shells in this facility likely approached a thousand.
Most were still under development.
Nanatsuki studied the tanks and noticed a critical detail:
Tetsuya had been growing Reishi Shells from embryos.
Many of the tanks held fetal or child-like forms.
This was different from his own method, and also from the Seireitei's.
Nanatsuki and the Seireitei used spiritual particles from adult Shinigami to create fully-formed Reishi Shells.
But here, Tetsuya's method involved natural growth from scratch.
"Starting from embryos… that means a much longer time investment," Nanatsuki thought.
In this world, spirits had Reishi-based flesh and blood, just like humans had physical matter. They aged, got sick, and died.
Even souls with Shinigami aptitude took much longer to physically mature than normal souls.
Raising an embryo to adulthood was no small feat.
"Tetsuya must have developed a way to rapidly mature spiritual bodies," Nanatsuki concluded.
The granddaughter of Mizutani Shingo had only been created in recent years—far too fast for normal development.
Nanatsuki remembered something else: when dissecting Tetsuya's creations, he noticed mismatched growth between the Spiritual Pressure Core, Soul-Chain, and Soul-Sleep compared to their bodies.
These were vital parts of any Shinigami's spiritual body—defining their spiritual strength—and in those Shells, they lagged behind.
This discrepancy likely stemmed from accelerated maturation.
Tetsuya had likely forced the body to mature until it could just barely sustain the Spiritual Pressure Core.
As the body developed, it stimulated development in the core and other parts as well.
Thus, he drastically shortened the time it took to grow an adult-like Reishi Shell.
"If I can obtain the rapid maturation tech, this trip will have been worth it," Nanatsuki thought.
Without the Sakkise interference here, he could now sense Reiatsu fluctuations.
He quickly located the strongest spiritual pressure on the floor.
"Yoruichi, go find the room where he stores his research logs. I'll take care of Miyamoto Tetsuya—he may already be captain-level."
"Understood," Yoruichi nodded.
Her original mission had just been reconnaissance. Now, with Nanatsuki's help, they could aim to capture Tetsuya himself.
Nanatsuki used Shadow Space to rapidly approach his target.
Upon reaching the vicinity, he expanded his shadow.
Tetsuya sensed the encroaching darkness and tried to retreat—
—but Nanatsuki had already tested this before, back when traveling with Yamamoto Genryūsai Shigekuni. His Shadow Space expanded faster than even Yamamoto's Shunpo.
At close range, escape was virtually impossible.
In an instant, the inky black space engulfed Tetsuya and pulled him inside.
"Quite the spacious lab you've got," Nanatsuki remarked.
"Even my Shadow Space can't cover it all at once."
Though the Mizutani were mid-tier nobles, their commercial success meant Miyamoto Tetsuya had unlimited resources. His experiments had scaled up significantly.
"Katori Nanatsuki..." Tetsuya's eyes widened.
"Didn't expect to meet you here."
"You've hidden yourself in the World of the Living for years, yet you still know me?" Nanatsuki raised a brow.
"Of course I do. I may be in the living world, but I'm not blind to what happens in the Seireitei," Tetsuya said, almost wistful.
"From being brought in by Katori Batsu'unsai to becoming captain-level in just over a decade—there aren't many Shinigami who grow that fast."
"And most of all... this body of yours—is just a Reishi Shell!"
Tetsuya's eyes burned with fervor.
"A mistake on my part. When Batsu'unsai brought you in, I didn't realize you were from that final batch of Reishi Shells."
"By the time I began looking into your record, it was too late."
Back then, Tetsuya was Third Seat of the Twelfth Division. He knew Kirio had once tried using Reishi Shell tech to heal Batsu'unsai.
But he didn't know the Reishi Shell Shutara Senjumaru had taken away ended up in Batsu'unsai's care.
He only realized the truth after hearing about Nanatsuki through Reishi Shell operatives and the Mizutani family—this rising star of recent years.
"But now... you've walked right into my lab," Tetsuya grinned, almost deranged.
"Such a precious subject—I must dissect you!"
"Let's see what secrets you're hiding!"
Suddenly, he swept his arm out—and all the surrounding glass tanks shattered.
Crash—!
Reishi nutrient fluid flooded the floor, and the Reishi Shells inside opened their eyes.
A dark red glint shimmered within their pupils—ominous and unnatural.
Just then, a streak of light flashed.
In a blur, over a dozen newly awakened Reishi Shells were sliced clean in half.
"So this is the swordsmanship of Katori-ryu... Outstanding!" Tetsuya laughed maniacally.
"But it's useless!"
The bisected Shells twitched—then their flesh began writhing, wounds closing up as if nothing had happened.
Fully healed in an instant.
"Is that your Shikai ability?" Nanatsuki narrowed his eyes.
He sensed some strange connection between Tetsuya and the Shells.
"Hadō #73: Sōren Sōkatsui!" Tetsuya chanted without incantation, but he didn't raise his hand.
Instead, the Reishi Shells all did.
Dozens of blue explosive blasts launched from them simultaneously.
Over thirty fiery strikes roared toward Nanatsuki, engulfing him in an instant.
BOOM—BOOM—BOOM—BOOM—BOOM!!