Jonggun is a fighter with legendary status and personal bodyguard for the daughter of the Head of HNH, Crystal Choi. He is also one of the "10 Geniuses" raised by Charles Choi and one of the three children that was reacted by Tom Lee. Gun would take off his glasses when he was about to show his demonic side, causing many to refer to him as a 'Monster'. Gun has a strict level of morality/rules for himself such as not engaging in illegal activities. he is the leader of a yakuza clan.