Chiho Kagari is Atsuhiro Kagari's younger sister, currently in middle school. She shares her brother's light blonde hair, usually worn in a ponytail. Like her brother, Chiho displays tsundere characteristics, though her outward expression differs. She is openly affectionate and welcoming towards her brother's girlfriend, Non Katagiri, whom she deeply admires, yet consistently masks her true feelings behind a blunt demeanor with others, particularly Masago Matsuo.

Her initial interactions with Matsuo, her brother's best friend who often visits to play dating sim games, show visible annoyance and frustration. She openly protests his presence and gaming. However, her behavior towards him gradually changes, revealing an underlying romantic interest. This shift includes moments of concern for him and active efforts to conceal her "dere" side, struggling to uphold her tsun facade as her feelings grow. Specific instances show her making lunch intended for him and seeking his help when frightened, such as during a spider encounter.

Chiho possesses sharp awareness of her brother's intense, often stalker-like admiration for Non, which disturbs her. Despite her own strong fondness for Non, she voices disgust at her brother's extreme actions, like meticulously calculating Non's eating habits. She participates in group activities with Akkun, Non, and Matsuo, including watching movies at home and attending events like New Year shrine visits.

She has a background in martial arts. Chiho's evolving relationship with Matsuo forms a significant part of her development throughout the series, contrasting with her brother's dynamic with Non.