Imouto ni Konyakusha wo Yuzure to Iwaremashita My Little Sister Stole My Fiancé: The Strong Dragon Favors Me And Plans To Take Over The Kingdom?

Synopsis

My sister took away my position as the Crown Prince's fianceé. In despair, I decided to become a sacrifice for the dragon. But somehow I was rescued by the dragon, and now we live together. (Source: MU)