She is the daughter of Oyafune Monaka, and is a maths teacher at Kamijou Touma's school. She notes herself that she has to rely on high-quality clothes and make-up to make herself to look good at her age, though from the narrative in the novels she would be a beauty if she takes off her glasses.

Even though her mother is one of the 12 people in the Board of Directors, she has not shown any connection with the dark side of Academy City so far.