Kii was a young girl presumably in her preteens like her boyfriend. She had neat hair with pigtails.
Kii had lived a happy life with her friends until the Dinosaur Empire appeared and ravaged part of Y City. In the ensuing chaos, Kii was killed in the outrage along with some of her classmates and townspeople. Her death was mourned by Masaru and caused him to seek revenge on the Dinosaur Empire.