Emi is a character in Daily Lives Of High School Boys that appears in episode 9
Background
Emi kicking Hidenori into the water
Emi first makes her apperance in High School Boys and Drop Kicks, when she kicks Hidenori into the river, thinking it's Kiyohiko. She is then thrown into the river when Hidenori pushes them into the water.
In High School Boys and the End of Summer, it is revealed that she has feelings for Hidenori. Before she can confess her feelings though, Hidenori reveals that they are cousins.
Emi after she finds out they're cousins