One possibility is that Yandere-kun - exactly like his female equivalent - is an emotionless boy who feels no reason to live...until he meets Senpai, and finally begins experiencing the same emotions and sensations that everyone else can experience. Yandere-kun would seek to eliminate anyone who threatens to take Senpai away from him, because Yandere-kun doesn't want to lose the one thing that makes him feel alive. Also he gay