As the second son, Kang-jae always felt he was in competition with his older brother who was always ahead of him. His inferiority complex continued in adulthood. He works as a real estate developer. His wish is to beat his brother just once in life. Throughout his childhood, he wore hand-me-downs that his brother wore. In high school, he was on the varsity baseball team but an injury and lack of financial support from his mom forced him to quit baseball. Because of this early career disappointment, he became a troublemaker. He rebelled against his mom who only doted on his older brother.
