Lee Soo Jin is the granddaughter of a master of Northern ITF Taekwondo, from which Renewal Taekwondo was derived from. When her grandfather divulged the secrets of the martial art after being defeated and captured by South Korean forces, her mother and grandmother were forced to work in the coal mines. There she fostered a burning hatred for South Korea and Renewal Taekwondo practitioners, particularly after a South Korean attack caused the mine collapse that killed her mother and many of the mine workers she grew to love as a family. Joining the North Korean military forces, she mastered her grandfather's art before discovering her nature as one the Keys, upon which she joined Nox and began planning her revenge against South Korea and Jin Mo-Ri. She later defects after being left to die i