Relations: Sister x Sister. is the debut eroge coming from developer Aile, releasing in Japan on April 28, 2011. The game's protagonist is faced with the not-so-daunting task of "adopting" two step-sisters, following his widowed father's decision to remarry. The older sister Kaori is great at everything and very popular at school, while the younger sister Chisato is just as pretty as her sister, but has a fear of men. Other girls soon find out about this, including his osananajimi Haruka, resulting in his life turning upside down.