Alice Soft - Ojou-sama o Iinari ni Suru Game

Kazuya is a high school student. But, Emiri, his classmate, uses him as a "tool" because when his parents passed away three years ago, Emiri's parents offered to take care of Kazuya and Chika, his younger sister, and Kazuya gratefully accepted it. His life is now full of chores. One day, he finds her secret by chance. "Emiri....it's my turn to give you orders...."