Asa Mizushima is a central character in the anime series 'Sora no Iro, Mizu no Iro'. She is portrayed as a high school student who is diligent and somewhat introverted. Asa is known for her gentle demeanor and her strong sense of responsibility, often putting others' needs before her own. Throughout the series, she plays a pivotal role in the unfolding narrative, where her relationships with other characters drive much of the emotional depth and complexity. Asa's character development is significant as she navigates the challenges of adolescence and personal growth.