Ore ni Amaete Kuru Yandere Gimai ga Motokano no Imouto Datta

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!