She is Eiji's younger step-sister. Though he always treats her as a little sister, Emi likes him in a non-brotherly way, always jealous of Shima and cannot bear her female classmates drooling about him. She gets involved in Shima's police cases but always manages to pull through without a scratch. She is the target of a not-very-clever neighborhood pervert, and is the object of affection of Yusuke.