Miki

Miki and Yuudai used to go out, or something like it, since neither of them are sure if they were ever a couple.
Mike is very fashionable and immodest. She has long nails and wears make up all the time. She appears outside Yuudai's apartment after having a fight with her boyfriend (Ken) and invites herself to stay the night.
She makes her self very comfortable and when Chizuru comes to Yuudai's to apologize the next day, doesn't even think of hiding herself.
She later makes up with her boyfriend.