Suzune Horikita

Suzune Horikita (堀ほり北きた鈴すず音ね, Horikita Suzune) is one of the main characters of the You-Zitsu series and the main heroine of the √Horikita spin-off manga. She is a first-year student of Advanced Nurturing High School and the younger sister of Manabu Horikita, the Student Council president of the school. She is seated at the back of the class and next to Kiyotaka Ayanokōji.

Despite her academic ability, she was placed in D-Class since she refuses to work with others. Nevertheless, she still strives for A-Class and will do anything in her capability to reach her goal.

Source: you-zitsu.wikia.com