Toshika Jin is Kaito Jin's younger sister and a first-year student at Tagane High School, approximately 16 years old like her classmates Monaka Yatogame and Mai Tadakusa. She originally favors her hometown over Nagoya yet adapts easily to new surroundings, maintaining a flexible perspective on regional differences. Her personal hobbies include collecting security devices. As Kaito's sister, she belongs to the Jin family unit.