Waga Itoshi no Wota Kanojo

A girl attends school only three days a week and is known for her frail health, intelligence, popularity, and striking appearance. She is referred to as the "mysterious heroine." The "ordinary protagonist" is a boy who lacks distinguishing traits and does not seem like a typical lead character. He falls in love with the girl without knowing much about her. It is later revealed that she is a dedicated but hidden otaku. The story follows his efforts to understand her interests while navigating the complexities of her hobby.