The trauma counselor. Mitomo lies to the students about there being a third killer. Mitomos intention in getting the students to murder/oust eachother is to get rid of the surviving male students. After the bus crash, he was made aware that his sister, Ami Toono, was pregnant. Mitomo had incestuous feelings towards his sister, and was kicked out of his home after their father walked in on Mitomo attempting to rape Toono. Mitomo thinks one of the surviving students is the person who got her pregnant, and wants them dead out of jealousy.