After a long discussion with Shiba Isshin inside the Urahara Shop revealing crucial truths about Sōsuke Aizen Shigure Sōsuke chose not to press further. He left Isshin behind to process everything and, without lingering, returned alone to Soul Society.
The weight of that information was more than enough to occupy Isshin for a long time.
As for the Quincy… Shigure did not bring it up again.
Though it was deeply connected to Isshin especially because of Kurosaki Masaki there was no need to force that revelation now. Some truths were better understood step by step.
Upon returning to Soul Society, the contrast was immediate.
Unlike the ever-evolving World of the Living, Soul Society moved at a slow, almost stagnant pace. Time seemed to stretch endlessly, and without urgent duty, life could even feel tranquil. One could sit in a courtyard, brew tea, and let centuries drift by unnoticed.
Yet even in such stillness, certain घटनाएँ could not remain hidden forever.
Shiba Isshin's disappearance eventually sent ripples through the Gotei 13.
As Captain of the Tenth Division, personally appointed under Genryūsai Shigekuni Yamamoto's authority, Isshin had led his division for years. Under his command, the Tenth Division once weakened after the loss of its previous captain had regained both strength and spirit.
No one expected him to vanish without a trace.
At first, Matsumoto Rangiku assumed it was just another case of her captain avoiding paperwork. It wouldn't have been the first time Isshin shirked his duties to wander off.
She searched throughout Seireitei, grumbling all the while
But found nothing.
As days turned into weeks, her irritation gave way to unease.
Then, to dread.
Rangiku was not merely carefree she was still a lieutenant of the Gotei 13. When Isshin's absence stretched far beyond anything reasonable, she realized the truth:
Something had gone wrong.
Suppressing her anxiety, she reported the matter.
The First Division was immediately notified, and under Captain Yamamoto's orders, an investigation began.
Despite the vast resources of the Gotei 13, no trace of Shiba Isshin could be found.
Gradually, two prevailing theories emerged within Seireitei:
One that he had defected.
The other that he had met with an accident.
The Central 46 deliberated extensively. In the end, they leaned heavily toward the latter.
Though the Shiba Clan had lost its status among the Great Noble Houses, its legacy still carried weight. Isshin himself had restored much of its standing through his service. More importantly, he was personally recognized by Yamamoto as someone worthy of command.
A man like that… was unlikely to betray Soul Society.
There was precedent.
Even in the case of Shihōin Yoruichi who had clearly aided Urahara Kisuke's escape her noble status complicated any official condemnation. Central 46 had been reluctant to act decisively then.
Now, with Isshin, the conclusion felt even clearer.
To confirm the truth, Kurotsuchi Mayuri of the Twelfth Division conducted a Reiatsu trace analysis using specialized detection equipment.
The result was absolute.
Shiba Isshin's Reiatsu had vanished.
Not only in Soul Society but also in the World of the Living and Hueco Mundo.
There was no trace.
Unless someone possessed an extraordinary method of perfectly concealing Reiatsu across all planes a feat bordering on impossibility there was only one explanation.
Mayuri trusted his instruments without question.
"To erase one's Reiatsu so completely would require technology or skill far beyond even captain-class norms," he stated coldly. "If such a method existed, I would already have developed it."
In his mind, there was only one individual who might rival him in such matters Urahara Kisuke.
But Urahara had long since disappeared from Soul Society's reach. The likelihood of Isshin encountering him under such circumstances was negligible.
Thus, the conclusion stood.
Shiba Isshin was dead.
For a Shinigami, the disappearance of Reiatsu meant only one thing.
Death.
Once Mayuri presented his findings, a heavy gloom settled over the Gotei 13.
The loss of a captain was no trivial matter. Even without knowing the cause, it reminded every Shinigami of the dangers inherent in their duty.
Nowhere was the impact more severe than in the Tenth Division.
Morale plummeted.
Matsumoto Rangiku, unable to reconcile the loss, took refuge in alcohol more often than not.
But Hitsugaya Tōshirō reacted differently.
When Isshin had departed for the World of the Living, Hitsugaya had believed it was to protect the division to shield them from a threat they were too weak to face.
Now, that belief turned into something heavier.
Regret.
Frustration.
Resolve.
He didn't know who his captain had fought.
He didn't know when the battle occurred.
He knew only one thing
He had been too weak.
If he had been stronger, perhaps Isshin would not have had to face that enemy alone.
Perhaps… he would still be alive.
That thought hardened into determination.
Hitsugaya threw himself into training with relentless focus.
Gifted with immense Reiatsu from a young age, he had already risen rapidly through the ranks, becoming Third Seat in a short time. His spiritual pressure had long since met the requirements for Bankai training, and he had already begun grasping its fundamentals.
But now, "almost" was no longer enough.
He would master it.
No matter the cost.
"I will become the captain of the Tenth Division," Hitsugaya declared quietly, his resolve unwavering.
Elsewhere, in the Fifth Division headquarters, Sōsuke Aizen stood in contemplation.
"What exactly happened…?" he murmured, adjusting his glasses.
After observing Isshin and Kurosaki Masaki in the World of the Living, Aizen had shifted his attention elsewhere. He hadn't expected Isshin to disappear entirely.
It was… unexpected.
Then his thoughts drifted.
To Masaki.
Judging by the time that had passed, the Hollow's influence should have progressed significantly.
How far had the erosion gone?
Had the Quincy succumbed… or adapted?
A faint, inscrutable smile touched his lips.
In the Thirteenth Division barracks, within a quiet chamber, Jūshirō Ukitake sat resting. His condition was slightly improved today, his breathing steadier than usual.
Across from him stood his lieutenant Shiba Kaien.
Ukitake looked at him gently.
"Have you given it thought?" he asked.
The question lingered in the still air, carrying weight far beyond its simplicity.