Yuu is Haruka's closest friend since junior high school. She often acts more conservative than Haruka, but occasionally gives in to Haruka's requests. Yuu initiates that she and Haruka do something special together, in order to comfort Haruka's growing insecurity of their friendship. But what began as a way to comfort a saddened friend soon turned into something much more for the both of them. She also shares romantic feelings for Haruka. Whenever Haruka tries to make Yuu kiss her, Yuu will often act embarrassed, but occasionally she will give Haruka surprise kisses.