Yi-jin Yoo

Yoo Yi-jin is the main protagonist of the Mercenary Enrollment/Teenage Mercenary manhwa. The story starts when Yi-jin, a young mercenary and victim of a plane crash, reunites with his family after a decade. He tries to be a normal high school student and protect the family he had not seen in years, but criminals and kidnappers thwart his path. He is also has shown to use Krav Maga, an a military self-defense and fighting system developed for the Israel Defense Forces.

(Source: Mercenary Enrollment Wikia)