Mercenary Enrollment (also known as Teenage Mercenary) is a Korean webtoon (manhwa) that follows Yu Ijin, a young boy who becomes a ruthless mercenary after surviving a plane crash that left him stranded in a war-torn region. After years of intense combat experience, he returns to South Korea to reunite with his family and attempts to live a normal high school life. However, his lethal skills, sharp instincts, and combat-hardened mindset quickly draw attention, leading to conflicts with bullies, criminals, and powerful organizations.