Male, also referred to as Teacher Cui, the balding homeroom teacher of Class Seven. He showed clear bias against Si Junni, only noticing her when both she and Li Yanyan were late. He frequently scolded Si Junni and accused her of disrespecting teachers and bringing shame to her martyr mother. On the bus, he demanded Si Junni move from the front seat but was outsmarted by her. He suspected Si Junni had been possessed by a Monster Beast due to her sudden change in behavior.
