Arima Squad (有馬班, Arima-han) was the squad originally under the lead of Kishou Arima himself.
During the Owl Suppression Operation and Rushima Landing Operation, it acted under the name Squad 0 (0番隊, Zero-ban-tai). It was tasked with eliminating any ghouls fleeing through the underground tunnels and defeating the Non-Killing Owl in case it penetrated from underground. The squad made its first appearance before the final battle against the One-Eyed Owl during the conclusion of the Owl Suppression Operation.
The squad would later appear during the Auction Mopping-up Operation as part of the S3 Squad (S3班, Esu-san-han). The squad would later defect from the Commission of Counter Ghoul during the Third Cochlea Raid to assist the One-Eyed King in his efforts to incite a revolution.
Kishou Arima, Koori Ui, and six unnamed and hooded investigators participated during the Operation of Suppression of the Owl under the leadership of Arima. In Tokyo Ghoul:re, Arima suppressed Shachi with two unnamed members, and Arima and several other nameless and hooded investigators defended Cochlea.
- Kishou Arima †- Squad Leader
- Koori Ui - Assistant Squad Leader (transferred to S1 Squad) (Formerly)
- Hairu Ihei † (transferred to S1 Squad) (Formerly)
- Haise Sasaki - Secretary (transferred from Quinx Squad) (temporary member between the end of Tokyo Ghoul and the start of :re) (Defected from CCG)
- Akira Mado (transferred to 20th Ward Branch Office) (Formerly; Defected from CCG)
- Rikai Souzu † (Defected from CCG)
- Shio Ihei † (Defected from CCG)
- Take Hirako (Resigned From CCG) (Went To Work At Mortuary)
- 4 Unnamed members (Killed during Third Cochlea Raid by Ayato Kirishima)
- Yusa Arima (Prior: Defected from CCG; Re:Chapter 179: Working with Quinx Squad)
Investigations and Operations
Owl Suppression Operation
Squad 0 split up individually to assist the other squads and convened when Arima made his second appearance in front of the real One-Eyed-Owl. Although appearing directly behind him upon their arrival, Squad 0 remained in the background and did not participate in the following fight that ensued. One member came to Koori Ui to help him up addressing him as "Senpai." After Arima had dealt a powerful blow to the One-Eyed-Owl, Squad 0 stood side-by-side with six identical sword-like quinque.
Auction Mopping-Up Operation
The squad later arrived and assisted in securing the building. The six hooded members of the team surrounded a wounded ghoul, Hinami Fueguchi, captured her and prepared to let their leader finish her off. Sasaki was able to prevent her extermination by gaining ownership rights of her, so the team departed with Arima to handle other matters.
Third Cochlea Raid
Arima Squad were assigned to defend Cochlea and later engaged Ayato Kirishima, Touka Kirishima and Renji Yomo in combat, during which several members were killed. They wield a quinque similar in design to IXA.
During the Third Cochlea Raid, Take Hirako and the rest of Squad 0 came across Haise Sasaki over Arima's dead body. Take Hirako called out to Sasaki, but called him "Ken Kaneki" and reassured him they were there to help him. While the younger members mourned their fallen leader, Hirako explained they were ordered by Arima to help Sasaki escape from Cochlea.
- Koori Ui, Take Hirako, and Akira Mado are the only members known to have been fully human. This squad mostly consists of half-humans. Only one of them is known to be a one-eyed ghoul.
- The members of Squad 0 all have identical quinques, often resembling IXA or long katanas that have a striking similarity to Yukimura 1/3, however it is unknown if the quinques are enforced to be identical or are identical for the sake of convenience.
- Tokyo Ghoul Chapter 138
- Tokyo Ghoul:re Chapter 84
- Tokyo Ghoul:re Chapter 34
- Tokyo Ghoul:re Chapter 60
- Tokyo Ghoul:re Chapter 38
- Tokyo Ghoul Chapter 80
- Tokyo Ghoul Chapter 141
- Tokyo Ghoul Chapter 142
- Tokyo Ghoul:re Chapter 31
- Tokyo Ghoul:re Chapter 65
- Tokyo Ghoul:re Chapter 70
- Tokyo Ghoul:re Chapter 85