Kasumi's younger sister. Asuka lives together with her parents and Kasumi, whom she simply refers to as "onee-chan" - Asuka is a year younger than Kasumi, however it's not always clear who is the more responsible out of the two. Asuka is a lot calmer than her sister and tends to be sarcastic and bad at showing her affection towards Kasumi. In the first season, Asuka was a third-year student at the junior branch of Hanasakigawa Girls' High School and in the same swimming club with Yuri. In the second season, she is a first-year high school student at Haneoka Girls' High School. She is also classmates with Ako and Rokka. (Source: BanG Dream! Wikia, edited)