Yandere Simulator
It is a popular indie game. Here, your main character is Ayano Aisha, a yandere girl who feels an attraction to a guy everyone calls Senpai. You will follow him like a shadow and keep away any girl who tries to approach him. You are allowed to use all possible methods - you can cruelly deal with her in the gateway, or act in a way for her to get expelled from school. You can even start killing everyone around. In other words, you will become a dangerous maniac in the body of the schoolgirl.