Mizu was born in Japan around 1637-38 to a Japanese woman who was raped by a white Western trader. There were only four such men in Japan at the time of her birth, and all Westerners had officially been forbidden from entering the country since 1633. Due to being seen as a half-breed monster or demon for her heritage, Mizu has usually concealed her blue eyes with a mask, wide-brimmed hat or tinted glasses, though she does not need them to aid her vision. She also has to hide her gender.