My Beloved Sister-In-Law Who Raised Me Single-handedly Was Taken Down By A Worst Friend... Nao Jinguji

Sister Nao and I are not real siblings. Nao was the stepchild of the partner whose father remarried when he was a student. After that, after my parents died in an accident, my older sister Nao became my parent. There was loneliness in our life together, but I also felt happy because I was in love with Nao. One day, my best friend, Yuzuru, was secretly talking to Nao, and when I approached him while feeling jealous, I was able to dodge it. And after a certain point, Nao's sister often came home late...