Earlier.

Retsu Unohana was quite satisfied with the conclusion of the ‘Emergency Meeting’. Captain Shunsui Kyoraku, who was always underestimated because of his playful nature, Isshin Shiba, the Shiba Clan’s greatest achievement in the last few centuries, and Isane, one of the best healers. With two Captains and her own Vice-Captain taking charge, she, like every other Captain present, felt confident that the matter would be resolved without trouble.

But then, another round of reports came from the 12th Squad, detailing a major threat that called for yet another emergency meeting. A powerful Vasto Lorde Arrancar had emerged in Karakura Town and Captain Aizen’s Reiatsu was detected on the scene.

Yamamoto didn’t intend to take any action as he trusted in Captain Shunsui’s capabilities. Isane barged into the meeting to pass Captain Aizen’s request, and the fact Shunsui had seemingly disappeared somewhere.

Yamamoto had no choice but to leave the Soul Society.

So, she, alongside Isane and Yamamoto, stepped through the Senkaimon. Isane prayed hard for Aizen’s safety, as he was one of the nicest people in the Gotei 13. Retsu didn’t hold on to false hope. In her mind, the best-case scenario was Aizen surviving with serious injuries so she could use her Shikai ability to heal him, while the worst outcome would be his death.

To her surprise, Aizen not only survived the strongest Hollow she had met, he brought her Reiatsu to the bare minimum where even Isane could’ve taken her down.

All the effort, however, went to waste.

“Why did you let her go, Commander?”

A Vasto Lorde’s death would have far-reaching consequences and disrupt the delicate balance every Shinigami sought to maintain. But sometimes sacrifices had to be made. Having an Arrancar that powerful swear revenge on one of their captains was no less than having a Sword of Damocles hanging over them.

After all, it was quite hard to find a worthy captain.

“We can’t purify her with Zanpakutō,” Yamamoto refuted her. “There are too many souls inside her… like Ikomikidomoe.”

“Ikomikidomoe?” Retsu’s brow furrowed in confusion, a name from the past resurfacing in her mind. “The Adjuchas you battled in your youth?”

Yamamoto’s grave nod confirmed her thoughts. “I’d have to use my Shikai to burn her away.”

Unleashing his Shikai in the Living World would kill half the town or perhaps more.

“Ikomikidomoe?” Isane chimed in with a question. “Captain, what is that?”

“An Ancient Hollow,” Retsu responded with a serious expression. “He was an Adjuchas who invaded the Soul Society a long time ago.”

“Just an Adjuchas? He’d have been slain easily.”

“He defeated me back in the days when Zanpakutō were rare,” Yamamoto confessed. “He became immensely powerful by bloating himself with over a million souls. An abomination like him couldn’t be purified, only sealed through the Royal Guard Ichibei’s technique... He is still sealed to this very day.”

Isane couldn’t help but blink her eyes. The entire story felt like a legend from a fairytale. “The Royal Guard stepped in to help the Soul Society? Does that usually happen when we face great calamities?”

“We don’t know.” Yamamoto glanced up at the ‘Urahara Shop’ sign on the building. “Urahara… Kisuke?”

Retsu noticed the subtle spike in Yamamoto’s Reiatsu. He still hadn’t forgotten the ambitious traitor who had used his fellow captains as experiment subjects. Despite her skepticism about the whole incident, Retsu couldn’t dismiss the possibility of Kisuke harboring dual facets to his character like herself.

‘As always, there is more to the story.’

The one who gave testimony to Kisuke’s crimes was Aizen — the same man who was found in the vicinity of today’s invasion.

“It’s him,” Aizen confirmed Yamamoto’s suspicion. “He might be behind the Arrancar Invasion.”

Aizen’s eagerness to paint Kisuke as the mastermind behind everything only made Retsu more skeptical. She kept her doubts to herself. After all, she couldn’t throw accusations at her fellow Captain without evidence.

Yamamoto’s eyes widened, revealing red pupils that rarely emerged. “Is he still inside?”

Aizen rose to his feet and pointed at the shop’s door. “Yes, he is. We have to seize him before he escapes.”

Retsu grabbed his wrist and gently struck his chest with her palm. Her serene smile held a hint of danger that even gave Aizen pause. “Captain Sosuke, I have stopped the bleeding. Please follow Isane to receive proper treatment at the medical facility.”

“But Unohana-san—”

“No buts. You will go with Isane.” Retsu considered the matter settled and turned to Yamamoto. “Commander, I’ll come with you to apprehend Kisuke Urahara.”

Yamamoto gave Aizen a long side glance. “Captain Sosuke, get well soon… You have much to answer for.”

“Yes, Commander.” Aizen respectfully nodded before he smiled at Isane. “I owe you my life.”

“I-I was just doing my duty, Captain Sosuke.”

…

As soon as the Senkaimon door closed behind them, Yamamoto used his cane to slide open the door and entered the shop. “A force-field. That explains why we couldn’t sense anyone inside.”

“He was a one-of-a-kind inventor,” Retsu said. “The founder of the Shinigami Research and Development Institute.”

She rarely gave anyone the moniker of genius, but Kisuke deserved the title for his unparalleled talent. Kisuke’s successor, Kurotsuchi Mayuri, was chasing in his footsteps to this very day.

‘Kurotsuchi can surpass Kisuke if he returns the Hollowfied Shinigami to their original selves.’

She looked at the row of rooms on the first floor. “Commander, let’s split up to cover more area.”

“Don’t confront him alone.”

“I know, Commander.”

Despite thoroughly searching every room, there was no sign of Kisuke to be found. However, in her search, Retsu stumbled upon a hidden door that opened up to an unexpected sight — a bright underground area. In the vast wilderness, she spotted many young teens dressed in Shin’o Academy’s uniform.

Among the thirty or something students, she could sense a familiar Reiatsu. She leaped into the air for a better view of the area and quickly located the source — a blonde Shinigami lying on a makeshift bed.

‘Rangiku?!’

She flashstepped to Rangiku’s side. A quick look and it was clear — the Rangiku before her now looked drastically different from the one in her memory. Her once shoulder-length blonde hair now reached all the way down to her ankles, a feat that was record-breaking for just a week’s time.

Retsu reached out to check on Rangiku’s health, only to have her hand grabbed by a young silver-haired boy.

“Who are you?”

Taken aback but maintaining composure, Retsu introduced herself. “I’m Retsu Unohana, Captain of the 4th Squad. What’s your name, young man?”

“Toshiro Hitsugaya.”

“I see. Do you know what happened to Rangiku?”

“Injured by Arrancars. Kazuya Nii-san’s Shikai healed her at the right time or...” He trailed his words with a clench of his jaw, eyes filled with remorse. “It’s my fault. My Shikai couldn’t kill those Hollows.”

Retsu hugged the young boy and stroked the back of his head, showing genuine warmth. “You were supposed to be having a simple field trip. We couldn’t protect you from the Hollows. Our competence caused you to suffer. None of this is your fault.”

She couldn’t let a young student bear the blame for the incompetence of their organization. If they had better preparations for an ambush, the situation wouldn't have reached this stage.

Toshiro pushed her back, glaring at her. “No need to coax me, Captain-sama. Yoruichi specifically requested my help in keeping the Vice-Captains alive. I failed at my job.”

“You know Yoruichi?” Retsu took a pause, realizing that the students weren’t at Urahara’s base by any mistake. “Why did she bring you here?”

Toshiro made a clueless face. “Yoruichi wanted to shelter us until people from the Soul Society took us back. Why else will Kisuke throw us in this dusty basement?”

Retsu’s pupils briefly flickered. From her observations, she could conclude that Kisuke wasn’t the perpetrator behind the Arrancar Invasion, else he wouldn’t protect the students. There was a chance Kisuke intended to use the students as hostages, but he should know the Gotei 13’s principles by now.

Killing a small thousand to save millions.

Yamamoto absolutely wouldn’t give in to any demands.

‘Captain Sosuke has to be lying.’

First of all, Aizen shouldn’t have been in the Living World, much less fight an Arrancar so out of an average Captain’s league. Yet, he survived the encounter and suffered barely any injuries. The Arrancar’s last words about Aizen’s victory also formed a different picture — one that sought to harm the Arrancar for his own ambition.

‘My gut feeling was right about Urahara and Yoruichi.’

The Yoruichi she knew were strong and compassionate, far from the kind to aid an evil man’s ambitions. 

‘Then Shinji Hirako and others…’

A shiver ran down her spine as she recalled the previous Hollowification incident. Aizen had been with them for nearly 150 years, perfectly putting on the mask of a gentle, kind person while scheming and experimenting on his fellow Shinigami.

She herself put on the mask to repress the bloodthirsty, vicious beast. But their motives were on different sides of the spectrum — she genuinely wished to heal others while Aizen put Shinigami through torture for his ambitions.

‘I have to inform the Commander. But first…’

With a gentle touch, Retsu ran her hands over Rangiku’s body, using her spiritual powers to conduct a thorough check-up. The results were surprising - Rangiku’s Reiryoku had become denser and more powerful, almost rivaling her own. This was quite a change from the last time Retsu had examined her a few years ago.

A Shinigami’s Reiatsu grew through near-death experiences, but it had its limits. One could not simply become a Captain-Class if their innate limit was that of a Vice-Captain. However, it seemed that Rangiku had gone through an extraordinary experience, which also caused her hair to grow exponentially.

She glanced at Toshiro. “Toshiro, do you know where Yoruichi and Kisuke went?”

Toshiro shrugged, his small shoulders rising and falling. “I do not know, Captain-sama. May I ask a question?”

“What is it?”

“Did you meet Kazuya Nii-san, by any chance?”

“Don’t worry about Kazuya. He went out to search for Vice-Captain Ise.”

After seeing Isane’s return, Retsu had first and foremost asked for Kazuya’s safety. This question prompted Isane to gush about Kazuya’s strength and how he saved both her and Isshin Shiba from Zommari’s ability to control people’s bodies.

Toshiro heaved a sigh of relief. “Thanks.”

Retsu nodded before she bent down and picked up Rangiku in her arms. “Students, come with me. I’ll escort everyone to the Soul Society.”

“Wait a moment.” He walked towards a red-haired student, who was sleeping with his back against a boulder. He bent down and flicked the red-haired student’s forehead. “Wake up, Renji. We’re leaving.”

Rubbing his forehead in annoyance, Renji awoke with a start and tears forming in his eyes. “WHAT WAS THAT FOR?!”

“STOP YELLING, IDIOT! WE HAVE TO LEAVE!”

“I AM NOT YELLING, DUMBASS!”

“YOU ARE.”

Retsu let out a soft giggle. The scene of Toshiro and Renji yelling reminding her of the bond between Isshin and Rangiku. The two bickered with each other all the time but their bond was deeper like every other Captain and Vice-Captain. Toshiro himself reminded her of Soi Fon - explosive temper with a deep sense of loyalty.

‘I haven’t seen her since that day.’

The day she provoked Soi Fon into picking a fight with Kazuya. Thanks to her mischief, Soi Fon faced defeat after a long time and became more driven to hone her craft.