|This article is about the adult version of Mion that appears exclusively in Yoigoshi-hen. For the younger version that appears in the main Higurashi no Naku Koro ni story, see Mion Sonozaki.|
|This article is about a side arc character in Higurashi no Naku Koro ni.|
Mion Sonozaki (園崎 魅音 Sonozaki Mion) is one of the main protagonists of the manga-exclusive arc Yoigoshi-hen and its visual novel adaptation. She's an adult woman who comes to Hinamizawa 20 years after the Great Hinamizawa Disaster in search of something at the Furude Shrine.
A woman of mysterious age wearing a kimono. She carries a katana with her and gives off a dangerous aura. A person from Hinamizawa who is more knowledgeable than Arakawa but has many secrets.
(Translated from Entergram's Higurashi no Naku Koro ni Hou website.)
Mion has green hair tied into a ponytail and wears a black kimono. She carries a katana and gun with her.
Mion is generally very serious and dislikes weak and cowardly people, however she jokes around sometimes. She also frequently pauses and reminisces on her childhood memories when traveling around Hinamizawa.
The Sonozaki Family had long held power in Hinamizawa, and each family head used a special hand bell to declare their succession. This bell was hidden away, and only Oryou Sonozaki knew of its location; after her death, the family faced internal disputes over who the next head should be. Mion was supposed to lead the family but nobody acknowledged her, and Akane became the head in her place. A rival Sonozaki faction led by Mifune arranged for Akane to get assassinated, and soon after Mion heads to Hinamizawa to find the bell and prove her legitimacy.
It is later revealed that Mion is actually an adult Shion, who took Mion's name when her sister died in the Hinamizawa school explosion. Mion's ghost had since followed Shion and stayed by her side, later possessing her. The visual novel version shows that with the original Mion's death, the Sonozaki family planned to say that Shion was actually the one who died while making Shion take Mion's place as the new head. Shion was in a bad mental state after the disaster however, and there was doubt as to whether or not she was fit to be the next head.
- Oryou Sonozaki (grandmother)
- Akane Sonozaki (mother)
- Shion Sonozaki (twin sister, vessel)
- Tatsuyoshi Kasai (ally)
Mion is first introduced when Otobe asks her for help and she mistakenly calls him Satoshi. After apologizing and introducing herself, the two of them head towards the Furude Shrine and encounter Yae Towada sheltering from the rain with her boyfriend Takumi. They rest there for a while, and Mion tells Otobe about the act of demoning away when Ryuunosuke Arakawa suddenly appears to report that he's found a car full of people who've committed suicide and wants to call the police.
The group is unable to call the police since their phones are disabled or out of range, and Mion later goes out to the ritual storehouse near the shrine with Ryuunosuke and Otobe following her. After breaking the lock with her katana, Mion begins searching for something inside the storehouse while the others start talking about a theory that alien parasites infected Hinamizawa long ago. Mion laughs at this crazy idea before giving them an ominous message that she's actually being possessed, prompting Ryuunosuke and Otobe to run out of the storehouse in fright. Suspicion is cast onto Mion's identity when Ryuunosuke reveals that she was supposed to have died 20 years ago in the Hinamizawa school explosion shortly before the Disaster.
Mion eventually finds the Tamahajiki sword but still needs to find a scroll, and Rika Furude's ghost appears to her and makes the scroll roll out before disappearing. Mion soon regroups with the others, and they hear Yae screaming outside. Mion learns that Yae was attacked and Takumi was kidnapped, and their car also disappeared. Mion searches around only to find no trace of any people or vehicles as Otobe tries to call the police again, however he dropped his phone earlier and it was mysteriously destroyed within a short time frame. The group returns to the meeting hall and discover Takumi's dead body, with Ryuunosuke leveling suspicion on Mion because of her katana.
Mion claims innocence as she could've killed everybody with ease if she wanted. She deduces that Otobe destroyed his own cellphone earlier for some reason and Otobe admits to it, soon confessing his past while claiming he never killed Takumi. Mion then deduces that Takumi was dead the entire time and Yae is responsible, as she's the only one who ever claimed Takumi talked. Yae admits that she killed him and explains why, but Ryuunosuke doesn't believe her. Mion then places her hand on Takumi's forehead and calls his ghost to give some parting words to Yae.
The group determines that Yae didn't lie about being attacked earlier, and they soon become surrounded by black-suited men; Mion swiftly dispatches them all. Mion explains to everyone that the black-suited men are part of a rival group to the Sonozaki Family and have been getting rid of their vehicles to isolate Mion and her companions. Mion then explains her goal of finding the bell and how it's hidden at the Sonozaki estate, with the Tamahajiki sword supposed to act as a key. Mion leaves her gun with Yae for self-defense, and the rest follow her to the estate. As they travel they encounter the car that Ryuunosuke had found earlier, and Mion shows new respect for Otobe after he pays his own respects to the dead people inside
They reach the estate only to encounter more of Mifune's men, and Mion takes them all out but gets shot by a henchman she was planning to spare. Mion finishes off the henchman but is losing blood and hands the Tamahajiki to Otobe so he can retrieve the bell, saying that her twin sister Shion will appear soon and asks him to give the bell to her. Otobe gets the bell but is cornered by Mifune at gunpoint, who wants him to hand over the bell or else he'll shoot. Otobe stands his ground and Mion arrives to slay Mifune.
Otobe thanks Mion and hands over the bell, however Mion gets confused and says she's actually Shion. It's then revealed that the real Mion had died 20 years ago when the Hinamizawa school exploded, and her ghost was watching over Shion for years. Mion eventually told Shion to go to Hinamizawa to retrieve the bell, and Mion began possessing her after Shion got into a car crash caused by Mifune's men. Shion then sees that her bullet wound disappeared, realizing that Mion had taken it with her after leaving her body.
Having completed her goal, Shion escorts everyone back to civilization, and they stop at the site where the school once was. Otobe tells Shion of Mion's last words that she hopes they'll be born as twins again, and Shion sheds tears before sticking her katana into the ground as a final thanks to her sister.