Shirakawa Hotaru

An active pianist in England and and old acquaintance of Inaho Shin. She is alumnus of Hamasaki High School, being one of the more famous people to graduate from there. She has released music albums and is called the "Eastern Fairy" for her prowess as a young pianist. She's in a long-distance relationship with Inami Ken.

Spoiler

To celebrate Shin becoming a father, she sends a video of herself playing a piano piece she composed; that piece is dubbed "Memories Off."