Keiko is a sophomore at Starlight high and she has always lived in the Valley. She is a second gen Japanese American and when her mom got arrested for manslaughter when Keiko was very young and her father tried hard to curve her and her sister so they wouldn't become like their mom who had ASPD which had gotten passed down to Keiko but not her sister Kasumi. She also has a "crush' on Kai but it's not a real crush, it's an obsession with him because he's one of the only people who made her feel normal and she chases the euphoria and feeling of normalcy that she chases after and feels the need for him to only need to be around her and no one else.

Keiko is a very popular girl at school knowing almost every student in her grade and a few more upper classmen. Despite her having ASPD she's very good at masking even though she is still extremely manipulative and a compulsive liar. You will never know if what she's saying if fact or not.

Keiko has a midwest accent soft quiet high pitched voice that's pretty monotone.