Kori was born to Mayor Morishita and his wife in the Fire Nation colony of Yu Dao, and was raised to honor both the Fire Nation Royal Family and her hometown. During her youth, she was given some form of earthbending training as well as additional weapons training, where she learned to use a meteor hammer. In early 100 AG, she met Sneers, a former Earth Kingdom rebel who had traveled to Yu Dao after the dissolution of his group, and the two of them fell in love and began a romantic relationship.