Imouto (Ane) wa Ani (Otouto) no Seiheki o Yugamasetai!

My older sister, Satsuki, is kind, caring, and soothing, and is the embodiment of the ideal older sister. My cute younger sister, Kae, is energetic and tomboyish, and she is attached to me, following me everywhere. I spent happy days surrounded by the two of them and our parents. ... However, there was a secret that only I didn