Hans is a robot created by Prof. Rama to look after his daughter who was blind from birth, Sita. Although Sita initially rejected Hans, her heart broke when the little robot managed to perfect the piano music Sita had created. When Hans's intelligence has exceeded the limits of his protocol, envy grows from a dark shadow that lodges in a giant tower, which then moves to stalk Hans and Sita. (Source: MangaUpdates)