Sayuri is a classmate and friend to both Juna and Tokio. She knows nothing of Juna's other life saving the planet, but tries to help her friend deal with what she sees as nothing more than emotions from her confusing personal life. While she at first tries to help Juna and Tokio remain together, it becomes clear she has feelings for Tokio herself, evidenced by actions such as her removing her glasses whenever she sees him, after he mentions that she looks better that way at one point. When her family is destroyed in the "death of Japan," she and Tokio look after her dying younger siblings.