Shion Sonozaki

Shion Sonozaki appears in Higurashi no Naku Koro ni Kai as the twin sister of Mion Sonozaki. A childhood swap tied to the family's heir tattoo left Shion raised as the "younger" twin while Mion carried the burden of heir apparent. Sent away to St. Lucia's Boarding School, Shion escaped in 1982 with the help of family bodyguard Kasai Tatsuyoshi. By the time of the story she works as a waitress at the Angel Mort restaurant and as assistant coach for the local Little League team, the Hinamizawa Fighters.

More outwardly refined and ladylike than Mion thanks to her schooling, Shion is in truth shrewd, manipulative, and mischievous, delighting in teasing her sister and Keiichi Maebara. Her feelings for Houjou Satoshi come to define her arc, and it is for his sake that she promises to look after his younger sister, Houjou Satoko.

Shion serves as the antagonist of the "Watanagashi" story arc and the protagonist of its companion arc "Meakashi": Satoshi's disappearance pushes her toward the Hinamizawa Syndrome, and consumed by paranoia and grief she is driven to a string of killings that end in tragedy. Other tellings of the same events instead see her grow close to Satoko as an older-sister figure, risking her life to protect her friends from the dangers threatening the village while gradually learning to master the emotions that once overwhelmed her.

Physically near-identical to Mion, Shion is distinguished by mint-green hair worn in a half-ponytail tied with a yellow ribbon, and she favors a stun gun as her weapon. The 20th-anniversary sequel manga Higurashi no Naku Koro ni Rei, set 35 years later, shows that Shion eventually married Satoshi.