Ore ni Amaete Kuru Yandere Gimai ga Motokano no Imouto Datta俺に甘えてくるヤンデレ義妹が元カノの妹だった; The Yandere Stepsister Who Spoils Me Was My Ex-Girlfriend's Younger Sister

Popular light novel author Ibarakino's Nocturne novel has been proudly adapted to manga by Harumare! On the day I was dumped by my clean-freak girlfriend Mishiro, my father suddenly remarried, turning Yuzuki a gal who is the spitting image of my ex into my younger stepsister. My life is changed at once by this little devil who does all the things my ex-gf didn't do for me! (Source: La France COMICS)