Nakajima Kazuko

She is Narumi's younger sister. She is friends with Akira and Junpei's girlfriend. According to others she is "stupid and lecherous".

Kazuko is a cheerful and open-minded girl who can get along with anyone. However, it is said that she does not get along well with her older sister Narumi. She is characterized by her glasses and braided hair.

She looks like a quiet girl with glasses, but in fact, she is a leader among the four because of her curiosity and aggressiveness. Even her boyfriend, Junpei is completely under her control. She is a very active person, and is very active with the opposite sex which she inherited from her older sister.

She is one to speak her mind and makes her feelings and words known. She helps her friends when they are unable to express themselves out loud. She likes what she likes because she's straightforward.