Kosaki Onodera is a high school student and one of the main characters in Nisekoi. She comes from a family that runs a traditional Japanese sweets shop, and she often assists with tasting and decoration. She has a younger sister named Haru Onodera. Since middle school, she has secretly harbored feelings for her classmate Raku Ichijou, who also has feelings for her, but both are unaware of the other’s affection due to their shyness. Kosaki is discreet, innocent, and slightly timid, yet she is very kind and caring, frequently looking after Raku when he is injured or ill. She tends to think carefully before acting, which leads to hesitation and difficulty in expressing her emotions. She has a natural affinity for animals and a passion for Japanese sweets, and she aspires to become a patissier. Her primary motivation is her love for Raku, but her self-doubt and concern for others’ feelings often prevent her from confessing. In the story, Kosaki is one of the dual heroines and a potential holder of a key linked to a childhood promise. Her key relationships include her close friendship with Ruri Miyamoto, who encourages her to be more open about her feelings, and her evolving bond with Chitoge Kirisaki, whom she initially sees as a romantic rival but later develops a trusting friendship with, often supporting each other despite the tension. Throughout the series, Kosaki grows from a hesitant girl into someone who can confront her emotions. It is revealed that she is the girl Raku promised to marry as a child. Ultimately, she confesses her love to Raku, who tells her he has fallen for Chitoge. She accepts this with maturity and grace, showing significant emotional development. Her notable abilities include a natural rapport with animals and a talent for making Japanese sweets, which she continues to pursue as a career goal.