Ushio is Tomoya and Nagisa's daughter.

She is a well-behaved, well-loved girl who is very curious about the world around her. Tomoya notes that she does not act like other girls her age. For example, most girls would want to have dolls; however, when Tomoya goes on a trip with her, he buys her a robot with which she is fascinated. Tomoya, finding it strange that she would prefer this type of toy, learns that Ushio has a some interest in robots; thus he also calls her "boyish." Ushio also appears to like baseball. Ushio's interest has been influenced by her grandfather who teaches her to imitate famous baseball players. She refers to Akio Furukawa as "Akki" and calls her grandmother by her given name "Sanae."

In the few earlier episodes of the stories, Ushio stays with Sanae and Akio. During her time with her grandparents, she learns to be a baseball addict like Akio, Ushio also learns strict disciplines from Sanae not to cry unless it is in the restroom.