An unusual girl in Kōichi's class. She is recognizable due to the eyepatch that covers her left eye, a doll's eye crafted by her adoptive mother. She claims it allows her to see the "color of death". At first, she is completely ignored by her classmates and sits in an old, scratched desk at the back of the classroom. Kōichi first meets her on the elevator of Yūmigaoka Hospital, and they gradually become closer. He defends her numerous times, particularly when faced with their very hostile classmates, some of whom believe her to be the "dead one" behind their year's calamity. She appears rather "doll-like" on the surface, but still has human feelings. In the novel and manga, Mei's doll eye is blue; in the anime, it is green.