Gogyo Jeongbeol: Iljin-gwa-ui Jeonjaeng

Doyul, son of the world's top assassin organization leader, transfers to a Korean high school! Arriving as a penniless transfer student, Doyul takes on a request from Dong-gu, a victim of school violence, and starts taking down the surrounding bullies one by one! (Source: Naver, translated)