“The Kōga Kuchiki Sealing Incident…”
Yanagawa’s gaze lingered on the record.
The entry stated: Kōga Kuchiki, son-in-law of Ginrei Kuchiki (grandfather of current Sixth Division Captain Byakuya Kuchiki), had murdered three comrades.
He was ultimately sealed in the World of the Living, Karakura Town, through the joint efforts of Captain-Commander Genryūsai Shigekuni Yamamoto and Ginrei Kuchiki.
The record ended there.
Concise.
Cold.
Standard for an official archive.
But Yanagawa frowned slightly.
“Three murders… and yet it required the Captain-Commander himself, along with the head of the Kuchiki Clan, to seal him?”
“This account glosses over far too much… almost as if it’s deliberately hiding something.”
From what he knew of Yamamoto, a mere internal homicide, no matter how serious—would never warrant his personal intervention.
Unless—
The crime, or the power Kōga represented, posed a threat severe enough to shake the foundations of the Seireitei.
Or worse… it touched upon a taboo that could never be made public.
The “murder of three comrades” was likely just the visible tip of a far larger iceberg.
Yanagawa silently noted the inconsistency.
The Kuchiki Clan.
The Captain-Commander.
A jointly buried truth.
This ran far deeper than it appeared.
[The Quincy Record]
Continuing onward, Yanagawa reached records concerning the Quincy, a history both grand and brutally inevitable.
For years, Soul Society had attempted to persuade the Quincy to relinquish control over Hollow extermination.
They refused.
As their numbers grew, the balance of souls destabilized.
In the end, the Shinigami were forced to eliminate them in order to preserve the cycle of souls.
“Maintain the balance of the world…”
Yanagawa repeated the phrase silently.
From Soul Society’s perspective, the logic was flawless:
Quincy eradicated Hollows completely.
This disrupted the cycle of souls.
Therefore, they had to be removed.
Yet beneath that justification lay the cold finality of genocide, and the one-sided narrative of the victors.
[The Hollowfication Incident]
Another record drew his full attention, more recent, and directly tied to his own background in the Kidō Corps.
“The Kisuke Urahara Hollowfication Incident.”
Central figure: former Twelfth Division Captain and head of the Research and Development Institute, Kisuke Urahara.
Participants/victims included:
Fifth Division Captain Shinji Hirako.
Eighth Division Lieutenant Lisa Yadōmaru.
Kidō Corps Vice-Chief Hachigen Ushōda.
Ninth Division Captain Kensei Muguruma.
And many others…
The list was staggering, nearly a third of the Gotei 13’s upper ranks.
Even the Chief Kidō Commander Tessai Tsukabishi and Vice-Chief Hachigen were implicated—both later disappeared.
Official conclusion:
Experiment lost control.
Multiple captains and lieutenants Hollowfied.
Classified as betrayal and threat to Soul Society.
Then came the turning point:
At the critical moment, Yoruichi Shihōin, head of one of the Four Great Noble Clans and commander of the Onmitsukido, stormed Central 46 and rescued Urahara.
Both fled Soul Society.
All Hollowfication victims disappeared as well.
…
Yanagawa felt a ripple of unease.
He had heard of this incident before, but the scale and implications far exceeded expectations.
Urahara Kisuke… a man who could involve so many captains in dangerous research, and inspire Yoruichi herself to betray Soul Society to save him.
This was no ordinary genius.
Nor a simple madman.
Yanagawa mentally reconstructed the event:
Leadership of the Kidō Corps disrupted…
Nearly half the Gotei’s command structure affected…
A noble house head staging a prison break…
“And yet,” he thought,
“the official record is vague where it matters most.”
The true motives, the nature of the experiment, the exact cause of failure—none were clearly documented.
This was no mere accident.
Something far greater lay behind it.
For now, Yanagawa set the mystery aside, but the name Urahara Kisuke etched itself deeply into his mind.
Continuing through related research records, Yanagawa encountered a particular entry.
It struck him like lightning.
“Tenshintai (Changing God Body)”
Inventor: Kisuke Urahara.
Function: Temporarily materializes the true form of a Shinigami’s Zanpakutō in the physical world through specialized reishi construction and stimulation.
Purpose: Enables direct, high-density interaction and combat with one’s Zanpakutō spirit, dramatically accelerating mastery of Shikai and even Bankai.
Note: Requires exceptional spiritual power and mental stability.
Risk of backlash.
Classified as restricted technology.” This chapter was taken from g.com without permission.
…
Materialize the true form of a Zanpakutō.
Yanagawa’s eyes locked onto the text.
His thoughts surged.
The mystery of the “Twin Hyōrinmaru” lay in the Zanpakutō itself.
All current investigation—interrogations, historical research, remained centered on the users.
But what if…
They went directly to the source?
If they could recreate, or refine the Tenshintai…
Not for training…
But to summon Hyōrinmaru itself.
Let the Zanpakutō speak.
Why had it chosen two masters?
Or at least… reveal clues through its manifested form.
Once the idea took hold, it spread through his mind like wildfire.
Compared to speculation, confronting Hyōrinmaru directly was far closer to the truth.
Even if it carried risk.
“Isshin,” Yanagawa said suddenly, his voice cutting through the silence.
“Hm?
Found something?” Isshin leaned in immediately.
Yanagawa pointed at the record and explained his idea clearly.
“…If we can reconstruct or understand this technique, we can bypass everything and ask Hyōrinmaru itself.”
Isshin’s eyes widened.
Then lit up.
“Yanagawa… what kind of brain do you have?!” he exclaimed.
“Let the Zanpakutō explain itself, kind of big brain.”
He rubbed his hands, excited.
“But this is Urahara’s tech.
It won’t be easy—and it’s restricted.
Where do we even start?
The Research and Development Institute?
And dealing with Mayuri Kurotsuchi… that guy’s a nightmare.”
Yanagawa’s gaze steadied.
“The Research Institute is unavoidable.
But first, we need more of Urahara’s research data.”
Isshin nodded firmly.
“Alright.”
As they left the Great Spirit Book Gallery, their next destination became clear.
If they wanted to pursue the Tenshintai—
They would have to face the Twelfth Division’s infamous “mad scientist.”
There was no way around it.