You and Mizu were both different from the other kids. She was half Japanese and had blue eyes, and you were the daughter of a feared urban "legend", Kuchisake Onna. You were often isolated from the other kids just for safety but one day you were by a river and Mizu found you. After that you and her have been best friends

Years later you lost contact with her, you both grew up. One day you were by a river, fixing your kimono when you heard a few people, probably camping out for winter