Kyoko Inaba is a main character appearing across multiple franchise installments. During her elementary school years at Doumori, she consistently wore a striped sando, short shorts, and a pink jacket. She had blonde or orange-red hair styled in twintails and blue eyes. Kyoko possessed a strong personality, readily using her strength to support classmates, though her fierce jealousy, particularly concerning Hiroshi Tateno and Miki Hosokawa, often resulted in her physically striking Hiroshi. She maintained an on-and-off rivalry with Miki, primarily focused on physical attributes like chest size and competing for Hiroshi's attention; this included situations like making deals where Miki played piano in exchange for Kyoko dancing in her swimsuit. Kyoko exhibited self-consciousness about her flat chest compared to peers like Miki. Academically challenged, she struggled especially with swimming, nearly drowning multiple times, and was known as a lethal chef whose cooking attempts typically resulted in unappealing sludge. She also demonstrated sensitivity to spiritual presences.

Kyoko's initial relationship with Hiroshi Tateno was antagonistic; she couldn't stand him when he first transferred into her class. However, she slowly developed hidden romantic feelings for him over time, embodying a Type B Tsundere dynamic. Their relationship evolved from rivals to one characterized by belligerent sexual tension, culminating in them becoming a couple. Kyoko shared a significant history with Meisuke Nueno (Nube), stemming from an incident where he saved her from a demon attempting to possess her when she was younger. This forged a lasting bond, making her one of Nube's most loyal and trusting students, and she actively assisted him and her classmates in confronting various evil spirits and demons encountered throughout their school years.

Twelve years after graduating, Kyoko returned to Doumori Elementary as a teacher. Her initial experience was challenging, as her class refused to listen and bullied her, causing significant stress and nearly leading to her resignation. This changed when Nube returned to the school upon Headmaster Ishikawa's request. Kyoko tearfully reunited with Nube, expressing how much she had missed him since graduation, and persevered in her teaching role with his support. Later, an illusionary version of her past self, created from a mirror imbued with her spiritual energy and emotions, appeared. This "Past Kyoko" initially expressed disappointment that her future self had not become a flight attendant as she had dreamed during childhood. However, after witnessing her future self heroically save student Yuria Tachibana from a truck accident, Past Kyoko was impressed and proud, acknowledging that Kyoko had become a cool and dedicated teacher who helped students like Nube, even if her childhood dream changed.

Ultimately, Kyoko permanently relocated to Italy to marry Hiroshi Tateno and build a life together there. Her background includes a possible past life connection to Nube. Her name etymology reflects "village, township" (郷) and "child" (子) for Kyoko, while her surname Inaba means "rice plant" (稲) and "leaf" (葉).