Kuraudo Ooishi, a veteran detective of the Okinomiya Police Department, relentlessly pursues the truth behind the Watanagashi Festival’s enigmatic deaths and disappearances. Born November 15, 1923, his father perished in a Nagoya air raid during WWII, embedding unresolved grief that deepened when a surrogate father figure—the manager of the Hinamizawa Dam Project—was murdered during a worker uprising. Ooishi blamed the Sonozaki family’s anti-dam activism for the death, igniting a decades-long vendetta. Post-war enforcement of black market regulations during food shortages further solidified his distrust of authority. A burly man with short grey hair, green eyes, and a chain-smoking habit, Ooishi dons a cream-colored suit, black shirt, red tie, and suspenders, often clutching an unused jacket. His demeanor oscillates between genial ally and intimidating interrogator, employing psychological manipulation and physical coercion to extract information. Villagers dub him "Oyashiro-sama’s Messenger," noting the eerie pattern of deaths following his interrogations, which fuels local superstitions. Driven to expose the Sonozaki family’s alleged orchestration of the annual "curse," Ooishi’s obsession fractures relationships, particularly with Mion Sonozaki, who rebuffs his accusations. Despite retirement plans to relocate to Hokkaido with his elderly mother, he continues collaborating with ex-colleague Mamoru Akasaka, compiling findings into *Higurashi no Naku Koro ni* to document the Great Hinamizawa Disaster. Key arcs underscore his influence: In *Onikakushi-hen*, his disclosures amplify Keiichi Maebara’s paranoia, precipitating tragedy. *Watanagashi-hen* sees him manipulate Keiichi to infiltrate the Sonozaki estate, while *Tatarigoroshi-hen* reveals his aggressive interrogation of Satoko Hojo, halted by Dr. Irie. The 1978-set *Himatsubushi-hen* depicts a younger Ooishi aiding Akasaka in a kidnapping rescue, showcasing dedication. Later arcs like *Matsuribayashi-hen* portray a mellowed Ooishi reconciling with Akane Sonozaki and indulging in mahjong, hinting at post-career tranquility. A skilled mahjong player and formidable combatant, Ooishi wields a firearm he rarely uses—until Hinamizawa Syndrome triggers violence in alternate timelines. Nicknamed "Detective Delicious" for his surname’s resemblance to *oishii* (delicious), he chuckles "Nfufufu" and harbors a passion for ballroom dancing, aspiring to teach it. His legacy, marked by moral complexity, intertwines relentless pursuit of justice with personal obsession, reflecting both systemic corruption and the enduring shadow of loss.