Estelle Brightman

In charge of the choir in Yo-han high school. A substitute teacher for only one semester who is also temporarily standing in for choir teacher who is on leave due to personal issues. She spent her student years in Japan where she got to know Ji-hye. Hence, she has a friend-like relationship with Ji-hye. Because of her open-minded attitude, she is popular with the students. However, she turns strict when she is teaching the choir. Her colleagues feel that if not for her laid back attitude, she would already be achieving great heights.