|This article is about a character in Higurashi no Naku Koro ni.|
|This article is under construction and may be incomplete.
Please be patient while the rewrite is in progress.
Kuraudo Ooishi (大石 蔵人 Ōishi Kuraudo) is a detective for the Okinomiya police department who is investigating the curse of Oyashiro-sama and aims to solve the deaths related to it before he retires.
Residents who have been in contact with Ooishi have disappeared due to Oyashiro-sama's curse, so he's known as "Oyashiro-sama's messenger" and is feared...
A veteran detective who is trying to uncover the truth behind the serial cases of mysterious deaths that occur every year in Hinamizawa. He's working hard to try to solve this case before he retires, but there are a lot of villagers who resent the fact that he's investigating this case.
Ooishi is a rather rotund middle-aged man with gray hair. He wears a black shirt with yellow pants, a red tie and red suspenders. He carries a jacket with him everywhere he goes but never seems to wear it.
Ooishi is very determined to solve the curse of Oyashiro-sama. His search for answers lead him to overstep his boundaries at times. He tends to be abrasive towards people he isn't already on good terms with.
Ooishi's father died in World War II during an air raid. After the war ended, the young Ooishi worked as a policeman and was responsible for arresting people trying to buy rice illegally. While chasing after a culprit one night, Ooishi was hit by another, older man that resembled Ooishi's father so much that he stopped running. Ooishi and the old man would then develop a close relationship, with Ooishi seeing him as a secondary father.
The old man eventually became the manager for the Hinamizawa Dam Project. When he was killed and dismembered on the night of Watanagashi in 1979, Ooishi became determined to solve his murder and avenge his death, later becoming known by the villagers as "Oyashiro-sama's messenger" due to him interviewing curse victims shortly before they died or disappeared. With Ooishi's mother growing old in 1983, Ooishi plans to retire and take care of her, but not before doing one last round of investigation.
- Katsuya Kumagai (subordinate)
- Mamoru Akasaka (friend)
- Tomoe Minai (friend)
- Keiichi Maebara (friend)
- Mion Sonozaki (friend)
Ooishi is first introduced. He interviews Keiichi regarding Tomitake's death, as they found his corpse on the side of the road with the names of Keiichi and his friends written on his shirt. Ooishi informs Keiichi of how Tomitake had apparently clawed his throat out and asks Keiichi to contact him if he learns any new info. Because of Keiichi's urban origins, Ooishi works closely with him in order to solve the mystery behind the curse. He later tells Keiichi of how Rena was previously institutionalized, how Satoko and Rika's family were all victims of Oyashiro-sama's curse, and the fact that all of the victims so far had some connection with his friends.
Keiichi confronts Mion about her family's involvement in the village. Mion is shocked by this, and while crying she curses Ooishi, saying that she showed him mercy this year because he was retiring, and that she should have killed him way back then.
During the chapter's climax, Ooishi suddenly gets a call from Keiichi, who ran to a phonebooth after being chased and is clawing his throat out while professing that Oyashiro-sama is real. Ooishi sends a police car to check up on him, and Keiichi is taken to the hospital where he later dies. Ooishi inspects his house to find the corpses of Rena and Mion. He also finds two notes written by Keiichi taped to the back of a clock, with signs that there was something else taped there. It is suspected that the two notes were originally one piece, but someone came in and ripped-off a section from the middle; Ooishi was later questioned, though he denied ever tampering with the note.
While Keiichi and Mion are walking home from school, they bump into Ooishi, who introduces himself to Keiichi while making some casual conversation with Mion. However this time, it becomes much clearer that the two have a history, with Keiichi sensing that the two don't seem to like each other at all.
Ooishi has a similar role from the previous arc, calling Keiichi in order to trade information. In his last phone call to Keiichi, he reveals that Shion disappeared on the same day as the mayor. This leads Keiichi to figuring out the true culprit behind the recent disappearances.
The next day, Keiichi and Rena prepare to confront Mion for her crimes, and run into Ooishi, who was waiting for Keiichi on his way to school. From this information Rena is able to discover Ooishi's true nature: He was planning on using Keiichi as an excuse to break into the Sonozaki main house, in the likely case that he went missing while under police supervision. Ooishi laughs, but he does not deny it. Both Rena and Keiichi see that Ooishi is willing to do anything to discover the truth that the Sonozaki Family is hiding, and leave the car insulting him. Ooishi says that they may not believe it, but he does not wish anything bad to happen to them if at all possible. Leaving them with these words, Rena and Keiichi go inside Mion's house.
During the epilogue, Ooishi visits Keiichi at the hospital, revealing that Mion was dead for over 24 hours when she stabbed Keiichi. Suspecting that Keiichi is hiding something, he interrogates him aggressively. Keiichi says he has no idea what he's talking about, and Ooishi leaves.
After seeing Satoko's state after being abused by her uncle. Keiichi is thinking about her while in front of the school gate. Ooishi soon arrives and asks to see Satoko. Keiichi somehow senses that Ooishi is bad news, and rudely asks him to leave. This angers Ooishi, causing him to press on Keiichi's shoulders until he's on his knees with pain. Irie interrupts Ooishi to help Keiichi, causing the detective to leave. Irie then reveals to Keiichi that Ooishi's been pestering Satoko for years, trying to get information out of her.
When Keiichi goes to check if Teppei's corpse is indeed where he buried it, Ooishi and several police officers suddenly appear. They coerce Keiichi to continue digging and soon finish the job for him, digging a big hole to find nothing. As Ooishi leaves, Keiichi curses him and wishes for him to die.
Later on, Keiichi takes Satoko to the Irie Clinic for treatment and overhears police officers saying that Ooishi and his assistant Kumagai have suddenly gone missing. Keiichi becomes convinced that he really did curse them to die.