She is Mizukis best friend from America. She comes to Japan to study for a month and finds out that Sano knows that Mizukis a girl. Julia tricks Mizukis classmates into thinking that she and Mizuki are lovers to gauge Sanos feelings for Mizuki. Nakatsu jealous that Julia is close to Mizuki in a way that he cant be takes a strong dislike in her as does she calling him Monkey Boy. sourse: wikipedia