Another spiritual signature vanished. Three of the reiatsu traces belonged to Fourth and Fifth Seat-level Shinigami, and one was roughly equivalent to a Fifth Seat.
Kurotsuki Renya sat quietly in his small room, jotting notes with careful detail.
The pattern of disappearances in Naruki Citycould only mean one thing: Aizen Sōsuke had begun targeting the Shinigami stationed in the Human World. These vanishing signatures lined up exactly with the covert experimentation Urahara Kisuke once warned him about—Aizen's early trials in merging Shinigami souls with Hollow reiryoku.
This incident would soon draw Shiba Isshinout from Seireitei to investigate personally. And just as planned, he would encounter the prototype Hollow—"White"—created by Aizen. At first, Isshin would attempt to suppress the creature, only to realize the Hollow's strength exceeded expectations, leaving him gradually overwhelmed.
Later, he would be saved by Kurosaki Masaki, who at that time was still a young Quincy. She would intervene using her natural reishi manipulation, but be struck by White and infected with Hollow reiryoku, forming the basis for the future Hollowfication within her body.
At that crucial moment, Urahara Kisuke and Isshin would converge. Isshin would make a choice—giving up his Shinigami powers through Urahara's Gigai to suppress the Hollowfication within Masaki.
From there, Masaki would continue her schooling, eventually graduating, entering university, and later forming a family with Isshin, leading to the birth of Kurosaki Ichigo.
But when Ichigo was nine years old, Yhwachactivated Auswählen, reclaiming the power of all mixed-blood Quincies. Masaki's hollow-core destabilized and she was killed by a Hollow attack she could no longer defend herself from.
Renya knew Isshin was about to appear in Naruki City, but he felt no urge to interfere.
He couldn't be exposed—not yet. His current condition allowed him to sustain peak combat output for only twenty seconds. That level was enough for ordinary Arrancar, maybe even Lieutenants, but nowhere close to confronting Aizen fused with Kyōka Suigetsu's illusions.
So he needed more time. Much more.
And Ichigo's birth was a crucial trigger point—an anchor in the timeline that needed to unfold unchanged. As long as Ichigo grew and events progressed naturally:
When Kurosaki Ichigo later entered Seireitei to rescue Rukia, Renya could infiltrate the Gotei 13 from the shadows, seek out Unohana Retsu, report to Yamamoto Genryūsai Shigekuni, assist in the crucial battles, and ultimately work alongside them in the final struggle to eliminate Aizen.
They could never allow Aizen to merge with the completed Hōgyoku. Once he did, he would gain an immortal body far beyond the reach of any standard technique. Even Ichigo's Final Getsuga Tenshō could not truly defeat him—Aizen only fell because the incomplete Hōgyoku ceased to grant him evolution.
Renya laid out his plan and continued to wait patiently.
Two months later, at last, a powerful Reiatsu burst into existence over Naruki City.
A Reiatsu of at least Captain-class.
Feeling it even from a distance, Renya recognized it instantly—this was Shiba Isshin, operating covertly, arriving in the Human World with no formal permission from Central 46.
Another reiatsu appeared.
This one was unmistakably Hollow in nature—the signature of White, the artificial Hollow created from the soul of a Shinigami, humanoid but with the bull-like mask and chest cavity of a prototype Vasto Lorde.
This creature would influence Ichigo's inner Hollow in the future—the origin of "Hollow Ichigo" itself.
Isshin would be driven to attempt Bankai against White, but Aizen would intervene from the shadows, striking Isshin at the exact instant he prepared to release it, damaging his body and preventing the activation.
The reiatsu fluctuated violently. After a short time, a third presence emerged.
A Quincy. The reishi signature was refined, clean, unmistakable—Kurosaki Masaki.
Three spiritual forces clashed in rapid succession before White's reiatsu finally vanished—Masaki sacrificing her right arm to deliver the finishing blow.
Minutes later, Isshin's reiatsu disappeared from the battlefield as he pursued Masaki. Quincy reiatsu vanished as well shortly after—Urahara taking charge of the stabilizing process.
With this, the true beginning of Ichigo's history had taken place. Renya released a soft breath. His presence had not altered the core events.
He stepped away from the warehouse rooftop and returned to his quiet room to wait.
Five days later, Yoruichi Shihōin approached him inside the warehouse.
"Renya," she said, arms folded, golden eyes serious. "Aizen just made his next move."
Renya turned toward her.
She continued, "A Shinigami named Shiba Isshin was attacked while investigating the deaths of his subordinates. He encountered a strange Hollow and was saved by a Quincy woman. She was infected with Hollow reiryoku. Isshin returned to the Human World, and Kisuke used a specialized Gigai to save her—but the cost was Isshin's Shinigami powers."
Renya nodded slowly. "In other words… Shiba Isshin can no longer operate as a Shinigami."
Yoruichi sighed. "Exactly. He's settling in the Human World now. Planning to open a small clinic in Karakura Town."
Renya asked quietly, "Do you and Urahara believe this was Aizen's doing?"
Yoruichi nodded without hesitation. "It has to be him. That Hollow had traces of Shinigami souls in its composition—a direct violation of the boundary between races. Only someone who understands the Soul-Breaking Boundary could create something like that. And Isshin attempted to use Bankai but was ambushed without sensing anyone else. We also know Aizen copied Kisuke's black cloak technology. All the evidence lines up."
Renya exhaled deeply. "And since Aizen knew Isshin would exhaust himself to protect the Quincy woman, he probably calculated every step. If he's already operating here, then he must still have agents inside Seireitei."
Yoruichi nodded again. "Kisuke asked me to bring you to him. He wants to know if you'd like to meet Shiba Isshin."
Renya paused. Then slowly nodded. "Of course I do."
There were many things he needed to ask—what Seireitei believed about his disappearance, how Soi Fon was coping, how Rukia and Asanjin Jūshirō were progressing, and how his former classmates were faring.
There were too many questions about the aftermath of his own declared death.
"Alright then," Yoruichi said, stretching lightly. "Let's go."
They left the warehouse and set off toward Karakura Town.
"Where's Captain Shiba now?" Renya asked as they leapt across the rooftops.
Yoruichi smirked. "Still at the Urahara Shop. He's panicking about what to do with his life now."
Renya nodded as they reached the shop.
Just as they stepped inside, a loud voice echoed through the store:
"Hey, Kisuke! You said you'd introduce someone important to me! What's with the secrecy? Hurry up already!"
The lazy, slightly off-key voice was unmistakably Shiba Isshin.
Kisuke's calm tone followed. "Captain Shiba, please be patient. They'll be here soon."
"Seriously, who's so mysterious?" Isshin grumbled.
Yoruichi slid the door open and stepped inside with Renya behind her. "I brought him," she said simply.
"Who is it?" Isshin asked, turning curiously.
Renya stepped forward, lowering the hood of his cloak.
The moment Isshin saw his face, his eyes widened.
"You… you're… Kurotsuki Renya?!"
He stood frozen, disbelief spreading across his face.