This article contains major plot spoilers from the manga that have not been revealed in the anime. Proceed at your own risk.
Koyuki Hinashi (氷無 小雪? Hinashi Koyuki) is Yuu's childhood friend and a popular singer. Following an incident where she and Yuu are seen in public together, she confesses her love for him on national television. After retiring as a solo musician, she secretly forms the band Rabbitz, whose members wear rabbit heads during performances.
A childhood friend of Yuu Haruna's. When they were in elementary school, she became a famous singer with a CD topping the charts in one week. She tries to contact Yuu through Twitter.
After Yuu moves to Tokyo and starts high school, they meet again when... She finally confesses the feelings she's held for him since childhood, but gets rejected. During one of the times they meet up after the confession, a girl catches them together and takes a picture of them, posting it on Twitter.
- Her three measurements are 80-56-83