Kuraudo Oishi serves as a detective at Okinomiya Police Station, born November 15, 1923. His father's death in a WWII Nagoya air raid created lasting family strain. Post-war, he policed illegal black markets during food shortages, a role causing moral conflict. During this time, he met an older man involved in the Hinamizawa Dam Project, who became a significant father figure. This man was lynched and dismembered by employees during a confrontation on the night of the 1979 Watanagashi Festival. Oishi believed the Sonozaki family orchestrated this event, fueling his drive to investigate Hinamizawa's annual mysterious deaths and disappearances, which he attributed to Sonozaki influence. Oishi possesses a muscular yet overweight physique, sports grey hair and watchful green eyes, and is a chain smoker frequently seen with Gaster cigarettes. His attire typically includes a cream-colored suit jacket carried under his arm, a black collared shirt, red tie, red suspenders, and dark brown shoes. He often forgoes the jacket due to summer heat and wears a watch on his left wrist. Five years of persistent investigation earned him the village moniker "Oyashiro-sama's messenger," as those he interviewed often died or vanished shortly after, fueling suspicion he was connected to the curse. Initially presenting as lighthearted and playful, Oishi reveals darker layers, demonstrating intimidation and a willingness to use violence or manipulation. His determination to solve the Hinamizawa cases before retirement borders on obsession, leading him to exploit relationships. He uses Keiichi Maebara as bait to access the Sonozaki estate and physically assaults Keiichi in Tatarigoroshi-hen, forcing him to his knees. Despite this ruthlessness, he occasionally expresses concern, such as reluctance for harm to befall Keiichi or Rena. His retirement plans involve relocating to Hokkaido, specifically Sapporo in some accounts, to care for his elderly mother, though he continues investigating the Great Hinamizawa Disaster post-retirement. His investigative role spans multiple story arcs. In Onikakushi-hen, he fuels Keiichi's paranoia by sharing curse details about victims connected to Keiichi's friends, culminating in Keiichi's death. In Watanagashi-hen, he deliberately withholds information about Shion's disappearance to provoke Keiichi into risky actions, intending to use any disappearance as leverage against the Sonozakis. During Tatarigoroshi-hen, his harassment of Satoko Hojo and physical confrontation with Keiichi demonstrate aggressive tactics. The 1978 timeline in Himatsubushi-hen shows him collaborating with Mamoru Akasaka to rescue a kidnapped child, highlighting dedication and camaraderie. Post-retirement in 1985, he and Akasaka co-author the book "Higurashi no Naku Koro ni" to document the Great Hinamizawa Disaster. Oishi maintains complex relationships. He views Keiichi as a useful outsider informant but strains their alliance through manipulation. His dynamic with Mion Sonozaki is adversarial due to accusations against her family, though they cooperate pragmatically in Tsumihoroboshi-hen. He initially distrusts Akane Sonozaki but reconciles in Matsuribayashi-hen, bonding over mahjong. His friendships include Akasaka, whom he assists in the kidnapping case; Kyousuke Irie, though he detects Irie's deceptions; and colleagues like Katsuya Kumagai, who disappears with him in Tatarigoroshi-hen. Trivia notes include his proficiency in mahjong, interest in ballroom dancing, wrestling skills defying his appearance, and the nickname "Detective Delicious" stemming from his surname's phonetic resemblance to "oishii." Though he carries a gun, he admits never using one prior to Tataridamashi-hen, where he succumbs to Hinamizawa Syndrome and commits violence against villagers.