She is Mizuki's best friend from America. She comes to Japan to study for a month and finds out that Sano knows that Mizuki's a girl. Julia tricks Mizuki's classmates into thinking that she and Mizuki are lovers to gauge Sano's feelings for Mizuki. Nakatsu, jealous that Julia is close to Mizuki in a way that he can't be, takes a strong dislike in her, as does she calling him 'Monkey Boy'. sourse: wikipedia