TG: Starting with Mangekyo

13th Ward, Seishin High School

"You've become the 'Cleaner' already?"

Standing by the edge of the rooftop railing, Arima asked Byakuya.

"Yes, Mr. Kaiko required me to assemble a Squad 0, and I've already appointed you as Vice-Captain. Sorry for not consulting you beforehand."

Byakuya said calmly.

"It's fine. Even if you had asked, I wouldn't have refused."

Arima responded with his usual impassive demeanor.

The fact that someone had taken on the role of Cleaner in his place was already a significant favor to him.

"Mr. Mustard has conveyed the mission. The base of the organization led by the One-Eyed Owl who attacked the CCG has been discovered. We've been ordered to eliminate it."

Byakuya shared the details of the mission with Arima.

"Let's go"

Without a word of hesitation, Arima immediately prepared to carry out the mission.

...

Back at the 2nd Ward's CCG branch,

The facility was still under repair following the destruction caused by the Owl attack a few days earlier, but investigators continued their work as usual.

The Squad 0 had officially been established within the CCG system, albeit currently consisting only of Byakuya and Arima, operating directly under the CCG's authority.

While Arima donned his signature white combat gear, Byakuya retained his black trench coat.

"Branch Chief!"

The investigators of the 2nd Ward greeted Byakuya with respect.

Now the youngest Branch Chief and a rising Associate Special Class Investigators, his reputation surpassed even some of the Special-Class Investigators.

Most believed it was only a matter of time before he ascended to the rank of Special-Class, especially after demonstrating his prowess by severing both arms of the Owl and forcing its retreat.

The last time the CCG had driven away an SSS rated ghoul, it was during the capture of the Dodgy Mother under Tsuneyoshi's direct leadership.

Byakuya acknowledged the investigators with a nod.

Since the quinque "Owl" was still under development, he had to rely on his worn quinques, 'Moonshadow' and 'Wind Spirit'.

This high-risk operation required both Byakuya and Arima to leave written wills before departing.

Though Arima typically turned in a blank page for such cases, this time he wrote something.

While Uchiha couldn't see the content, he could guess it was likely addressed to Minami, given that Arima's previous blank pages stemmed from having no one to write to.

Byakuya, too, penned a letter—his addressed, of course, to...

"To Sen Takatsuki"

With preparations complete, the two set off for the Aogiri Tree's base of operations.

...

Inside an abandoned, dilapidated house

The ghouls of Aogiri Tree gathered in a somber huddle, their numbers limited to a few dozen elite members, each at least A rated. Eto had yet to expand the organization due to financial constraints.

"It's strange. Who was that 'One-Eyed Owl' who attacked the CCG last time? Eto was with us the whole time, wasn't she?"

"No idea. Must've been someone impersonating her, but the resemblance to her kagune is uncanny!"

"Do you think it might be a relative of Eto's—?"

"Shh! Don't spout nonsense. Eto has said she has no family."

Frightened of angering Eto, the group fell silent, though some privately speculated that such similar kagune traits could only exist among close kin.

To conceal her identity, Eto refrained from using her family name, Yoshimura, in the presence of her subordinates. The name Kuzen Yoshimura was infamous among ghouls, known for carving a bloody legacy.

As a natural half-ghoul, Eto could perfectly masquerade as a human, which was how she had revealed her name to Byakuya to secure the publication deal — before knowing he was an investigator.

Lost in thought about her father Kuzen, Eto was interrupted by a scout bursting into the room.

"Bad news! Two Doves are here!"

"What?!"

"The Doves found us? Was our location compromised?"

"Prepare for battle! Don't let them leave alive!"

The ghouls braced themselves.

Eto, too, threw her personal concerns aside, cloaked herself in a black hood to hide her identity, and prepared for combat.

She couldn't fathom how their base had been discovered but resolved to relocate immediately after eliminating these Doves.

In hindsight, she regretted not relocating sooner. Her dealings with that lolicon investigator had delayed her plans.

And just as she cursed him mentally, Byakuya and Arima stepped through the door.

The sight of Byakuya left her momentarily stunned.

"Stand down!"

As the ghouls prepared to attack, Eto halted them.

Confused, they looked to her for guidance, hesitant to act without her command.

"All of you, retreat" Eto ordered in a voice altered to avoid recognition.

Facing him would be suicide for her followers, and she wouldn't let them throw their lives away, she turned to Tatara.

"Tatara, take them and leave"

Tatara, a white-haired ghoul wearing a red mask, who served as Aogiri's strategist.

"...Understood"

Tatara hesitated but obeyed, leading the others to safety.

As Tatara led the group away, Eto transformed in her full kakuja form, attacking Byakuya and Arima to buy time.