Mercenary Enrollment follows Ijin Yu, a teenage boy who survives a plane crash as a child and is forced to become a highly skilled mercenary to stay alive. After years of brutal training and missions, he finally returns to his family in South Korea, hoping for a normal high school life. However, his dangerous past catches up with him as he uses his deadly abilities to protect his loved ones from threats like bullies, criminals, and rival mercenaries. Readers enjoy the series for its mix of intense action, satisfying revenge moments, and the heartwarming contrast between Ijin’s violent skills and his genuine desire to care for his family and make up for lost time.