A mysterious teenage girl found by Hyougo Otoo during his travels, Aoi Yamada arrives at the restaurant claiming to be an orphan whose parents died in a house fire. This story quickly unravels due to inconsistencies: she fails to respond to her supposed surname and possesses a fully loaded luxury suitcase. Her actual past involves running away from home following conflicts with her older brother, Kirio Yamada, whom she resents for eating her favorite natto. Her mother, Kikuno Yamada, is caring but initially struggles to connect with her. With nowhere else to go, she takes refuge in the restaurant's attic, habitually stealing food and utensils, leading to repeated confrontations with staff members like Jun Satou, Kyouko Shirafuji, and Souta Takanashi. Though hired as a waitress-in-training, her performance is poor; she frequently breaks dishes, consumes customer orders, and displays general clumsiness, increasing the workload for others. Her lack of social boundaries manifests in inappropriate behavior, including phoning coworkers at late hours and insulting those she dislikes. Her personality blends blunt honesty with manipulative tendencies. She openly reveals Jun Satou's feelings for Yachiyo Todoroki, causing turmoil, and later assembles an idealized "family" unit within the restaurant: designating Otoo as her father figure, Yachiyo as a mother substitute, and Hiroomi Souma as a brother. This stems from a deep-seated yearning for familial connection, despite her real family remaining alive and searching for her. She exhibits academic difficulties, having failed entrance exams multiple times, and misinterprets her mother's study aids as pressure rather than support. Relationships with coworkers are complex. Souta Takanashi sees through her deceptions and occasionally cares for her, though she harbors resentment toward him for nearly exposing her past. Souma, despite initially resisting her demands, becomes a reluctant brother figure after gifting her a teddy bear named Daisy, which she cherishes. Yachiyo shows her kindness, partly due to her resemblance to Kyouko, while Popura Taneshima and Inami Mahiru act as mentors and friends. She avoids discussing their romantic feelings for Souta to prevent conflict between them. Her development involves gradual reconciliation with her family. Kirio actively searches for her, and though she initially rejects him, she eventually reconnects with her mother, recognizing her intentions were misunderstood. By the series' conclusion, she continues working and living at the restaurant while maintaining ties with her biological family, striking a balance between her constructed and real relationships.