Hanako is Senpai's younger sister. She loves her big brother more than anything in the world and depends on him for almost everything. She is very possessive of him and becomes upset when he won't spend time with her.

"Onii-chan! There you are!" Hanako hugs her brother, Taro Yamada, Affectionately. Hanako is deathly afraid that if her brother gets a girlfriend, he'll forget all about her and refuse to spend time with her.