|First Appearance||Higurashi no Naku Koro ni Mei|
|Portrayed By||Rie Takahashi|
A girl from Tokyo. It seems she visited Hinamizawa for a certain purpose, but her real intentions are unknown. Has absolute confidence in her good sense and intuition, and never breaks from her bullheaded attitude.
Nao is the younger half-sister to Rena Ryuuguu who was born after Reiko Ryuuguu divorced Yasunori Ryuuguu and married Akihito Houtani. While Nao was in elementary school, Reiko and Akihito divorced. During Japan's 1990s recession, Reiko went bankrupt and could no longer afford the tuition to Nao's school. Shortly afterwards, Nao ran away from home and contemplated suicide.
She visits Hinamizawa, hoping to meet Rena's spirit upon her death, and ends up traveling back in time to 1983.
Nao appears as young girl with long auburn hair and blue eyes. She typically wears a black dress with white stockings and black shoes.
Nao is a resilient yet troubled girl. Her fractured relationship with her parents makes her act unusually independently for her age.
Higurashi no Naku Koro ni Mei
Nao appears as a major character in Higurashi no Naku Koro ni Mei who helps Kazuho Kimiyoshi and Miyuki Akasaka fight tsukuyami as they attempt to solve the mysteries surrounding Hinamizawa after entering a portal to 1983. In Chapter 8, she reveals her relationship to Rena Ryuuguu and two express their joy at being able to meet each other, albeit briefly. After she returns to the portal and tries to go back to 1993, she and Miyuki end up in a version of 1998 wherein Hinamizawa has been submerged underwater.