She is Yumegaoka year 1, class 2's homeroom teacher. She is also the Diving Club supervisor, adviser, and consultant. She shares an interest in scuba diving with Hikari. She had a competition with Hikari when she first went to school and realized that they were diving buddies. Her car is a Nissan Cube (a mini MPV) called "Pokoteng 3rd-kun." It is very possible the same character in the manga iRoman Club shares exactly the same name with Katori Senkou's older sister. (Mangaka Amano Kozue tends to cross over blood relatives of main characters.)