Hwujin is a tall, muscular man who sports unkept, shoulder-length black hair. He carries a laid-back and joyful disposition, though this changes when he deals with corrupted teachers and juvenile delinquents. He is also known for his role as a TRPA (Teacher's Resource Protection Agency) warden. Despite this, he is often seen with a relaxed expression, perhaps reflecting his deep devotion to the TRPA's mission.