Help! A Yandere Won't Leave Me Alone!

I only saved him a few times, but he latched onto me and insisted on calling me his big sister. I treated him like a little brother, while he treated me like his wife. Later, I went to him to prove that I liked him too, only to discover that the sweet, adorable little boy from my childhood had all been an act! He’s a total pervert! “Big sis, what do you like about that person? Want me to give it to you~”