Mitsui (三井?) is a student of Hikarizaka Private High School who first appears in The Scenery With a Carving. She talked with Fuko for a bit during the school's entrance ceremony before her accident. Though she remembers Fuko, she refuses to accept Fuko's starfish sculpture gift and request to go to her sister's wedding, since she is a senior and is busy with entrance exams. This hurts Fuko's feelings. In the visual novel, Mitsui is shown to be more antagonistic towards Fuko (rather than the mere indifference that can be taken from her anime interpretation); for example, she berates Fuko's continued attempts to distribute her starfish sculptures to the senior class that Mitsui represents, calling Fuko a nuisance to the other students' studies.