Kishō Arima served as a Special Class Ghoul Investigator for the CCG, earning renown as its most formidable operative and the nicknames CCG's Reaper or White Reaper through unmatched combat skill. His eighteen-year career included leading the elite S3 Squad and decisively influencing major operations. While famed as a human investigator, Arima secretly operated as the One-Eyed King, allying with the ghoul Eto Yoshimura to orchestrate societal change. This alliance led him to claim Ken Kaneki after the Owl Suppression Operation, intending to mentor him as his successor. Arima possessed a tall, muscular build, snow-white hair, and gray eyes, consistently wearing thin-framed glasses and maintaining a stoic expression. On duty, he wore the S3 Squad's signature white coat over professional attire. In his youth, he had dark blue hair and carried his quinque concealed in a guitar case while posing as a student. His personality exhibited extreme calm and calculation, even against threats like the One-Eyed Owl. He demanded precision, famously reprimanding his partner Take Hirako for a 0.1-second delay. Despite his冷酷 demeanor, he formed bonds, displaying "parental love" toward his protege Haise Sasaki and respecting the deceased, chastising colleagues who spoke ill of fallen investigator Kureo Mado. Arima's career began in his teens, depicted in *Tokyo Ghoul: Jack*. At 16, promoted to Rank 3 Investigator, he partnered with Taishi Fura to eliminate the ghoul Lantern. He uncovered Uruka Minami's true identity as Lantern and defeated her; by that age, he had already killed over thirty ghouls single-handedly, including Hikari Kirishima. He later played pivotal roles in major conflicts, wounding the original One-Eyed Owl (Kuzen Yoshimura) and crafting the SSS-rated quinque Owl from its kakuhou. In a covert meeting, he spared Eto Yoshimura upon learning her ideals, forming a secret alliance. During the Owl Suppression Operation, Arima confronted Ken Kaneki in Route V14. He effortlessly overpowered Kaneki, impaling his skull and eyes with the quinque IXA, inducing amnesia. After Kaneki's imprisonment in Cochlea, Arima monitored his deterioration, intervening by providing stabilizing books. He later guided Kaneki in creating the identity "Haise Sasaki" using kanji from the words for "coffee" and "world". As Haise's mentor in *Tokyo Ghoul:re*, Arima supervised the Quinx Squad. He permitted strategic decisions like Urie Kuki's frame release surgery and subtly encouraged Haise's reconnection with his past, such as when Haise claimed ownership of the captured ghoul Hinami Fueguchi. Arima's combat abilities stemmed from his half-human physiology, granting enhanced strength, speed, and reflexes but causing a shortened lifespan. He aged rapidly, developing glaucoma and joint deterioration by his early 30s. His tactical genius allowed him to deduce opponents' weaknesses, identifying Eto as the One-Eyed Owl and recognizing Kaneki's potential during their first battle. He wielded multiple quinques: Yukimura 1/3 (koukaku sword), IXA (versatile koukaku lance-shield hybrid), Narukami (ukaku lightning-projecting weapon), and Owl (SSS-rated ukaku blade). He destroyed IXA in his final battle against Kaneki. In the Third Cochlea Raid, Arima confronted Kaneki, now restored. After a protracted duel where Arima acknowledged 645 opportunities to kill Kaneki, he was disarmed. Revealing his half-human nature and affiliation with V, he declared Kaneki the new One-Eyed King. He then committed suicide by slitting his throat, stating he had "finally left something behind". His legacy endured through Kaneki, who adopted Arima's title and mission to dismantle the Washuu dynasty and V.