Tsukuyomi Komoe

Despite her childish and very short (135 cm) appearance, she is actually an adult and one of Tōma's teachers; this is proven by her apartment being littered with beer cans, cigarettes and neuropsychology books. She also contradicts her age by acting childish to her students, having a child-like crush on Tōma, and ending her sentences with desu, something a child usually does; this irony means that she is often regarded as one of the seven great mysteries of Academy City. She has major interest in studying and performs magic once, when Index requires her to participate in a magical ritual to heal her wounds, meaning she is one of the few non-psychics in Academy City.

In volume 9, is stated by Yomikawa Aiho as being a teacher even older than herself that scarily looks fitting in cheerleading clothes, and in the author notes at the end of volume 5 states Komoe is the oldest female character currently in the novels.