Kiho Kurihara is a high school student and a member of the main friend group that includes Kadode Koyama and Ouran Nakagawa. She has brown hair worn at neck or medium length and brown eyes, and is noted for having a slightly more feminine style and an attention to her appearance compared to the other girls in her circle.

Her position within the group is defined by a sense of being an outsider. Unlike the other four friends who have known each other since before high school, Kiho only joined the group after entering high school, which gives her persistent feelings of isolation and distance from them. This feeling of being on the margins of the group dynamic shapes her personal journey.

In an attempt to forge a closer connection, Kiho begins a romantic relationship with Kenichi Kohiruimaki, a classmate known for being a quiet and isolated figure. This decision further distances her from her four female friends, as she becomes absorbed in the relationship. However, the relationship proves to be fraught with difficulties. Kenichi tends to be preoccupied with information from the internet and lacks the emotional empathy Kiho needs, leading to frequent disputes and the eventual dissolution of their romance. After the breakup, Kiho reconciles with her original friend group and reestablishes her close friendships with them.

Tragedy defines the end of Kiho's role in the story. During an incident where a medium-sized alien ship, attacked by the Japanese Self-Defense Forces, crashes into the city center, Kiho is caught in the resulting catastrophe and loses her life. Her sudden and violent death serves as a devastating turning point, profoundly affecting her close friends and altering the course of their futures. The event also has a deep impact on her former boyfriend, Kenichi, who experiences a profound change, joining a radical group and descending into a much darker state of being as he struggles with his grief and loss.