The daughter of Sonezaki Souichiro, born on October 10, 1985. She is a first year at Toritsu Shinnet High school and is in the kendou club. Yui is generally a nice, mild-mannered girl who will stop to feed any hungry animal she sees and even bring the animal home. She sometimes can be short tempered and fragile. Her father owns a curry restaurant, but when the business fails he goes to sharpen his cooking skills, leaving the restaurant to Yui. Despite the fact that her father abandoned her, Yui still loves him and his curry cooking. When Yui meets Makito she teams up with him to save the restaurant. She tries to help Makito as much as possible and comes to admire and respect his ways. She likely harbors feelings for him.