Kyōko Hori is a popular and academically successful high school student at Katagiri Senior High, known for her energetic presence among peers. This public image masks a contrasting domestic life; her parents' frequent absence forced her into managing household chores and caring for her younger brother, Souta Hori, from a young age, limiting her social and extracurricular activities since junior high. Her appearance features chestnut-colored hair often tied in practical ponytails or buns at home, golden-brown eyes, and a slender build standing approximately 163 cm tall. At school, she wears seasonal uniforms with light makeup, switching to plain T-shirts and leggings without makeup at home. Hori's personality blends diligence with volatility. She achieves consistently high academic scores, exceeding 90% on tests, and manages domestic responsibilities rigorously. Embarrassment or nervousness often triggers aggressive reactions, like physical outbursts toward her father. She exhibits intense focus during mundane tasks like ear cleaning or massages, causing apprehension in others. A notable trait is her request for Izumi Miyamura to adopt an "abusive boyfriend" persona, fulfilling her masochistic preferences, which she finds refreshing despite his reluctance. Her development centers on her relationship with Izumi Miyamura, whom she meets after he assists Souta. Discovering each other's hidden selves—her home responsibilities and his piercings and tattoos—they agree to mutual secrecy. Initially viewing Miyamura as a dependable friend, her feelings evolve into romantic attraction. She overhears his confession while feigning sleep and later acknowledges their relationship when confronted by her father. Their bond deepens through shared experiences, confronting his past bullies and navigating her separation anxiety. Jealousy emerges as Miyamura gains popularity, earning her the nickname "Hannya" (Goddess of Jealousy) from peers; she later tolerates his interactions with women while expressing aversion to him forming romantic bonds with men. Key relationships include her role as Souta's primary caregiver, occasionally evoking his fear of her aggressive tendencies. Her father, Kyousuke, notes her resemblance to her mother, Yuriko. Among friends, she rejects Tooru Ishikawa's early romantic advances but maintains their friendship; she withholds her domestic life from Yuki Yoshikawa, initially lying about Miyamura's identity. Her childhood dynamic with Kakeru Sengoku involves teasing him, though they reconcile during high school. The narrative concludes with her marriage to Miyamura, adopting the surname Miyamura, and having a son named Kyouhei. Trivia includes her double-jointed fingers, allergy to blueberries, dislike of stew and citrus flavors (excluding mikan), and difficulty with tongue twisters despite academic prowess. Her favorite anime is "Riho's World," she enjoys horror films, and she ranked second in a series character popularity contest.