Oneesan is the heroine of the story.<br /> <br /> She is the calm sister Boku-kun meets at a bus stop in the countryside on a rainy day. She is very tolerant of ecchi and rather actively initiates and leads Boku-kun in doing ecchi with her. She also lactates.<br /> <br /> The CV will be played by Natsuki Nogami (野上 菜月) in the first part and Mei Goenou (御苑生 メイ) in the second episode of the middle part.<br /> <br /> (Source: ch.dlsite.com/matome, translated)<br /><br />