Nodoka is Yui's childhood friend and confidant, who is a member of the school's student council. As a normal, well-mannered and intelligent girl, she is generally taken aback by the light music club's odd behavior. She shares the same class as Mio in their second year, who appreciates her companionship tremendously, since she being the only person Mio knows in her class. In her third year, she becomes the student council president and is also in the same class as the other third year club members. She gradually becomes the president of Mio's fan club through means that was not within her will.

Source:Wikipedia