Gamemaster

A gamemaster (simplify as GM, also known as game master, game manager, game moderator or referee, and guán lǐ yuán 管理员, zhǔ chí zhě 主持者 or shén 神 in Chinese, gamemaster ゲームマスター, kanrisha 管理者 or kamisama 神様 in Japanese, MJ for "Maître du Jeu" in french) is a person who acts as an organizer, officiant for questions regarding rules, arbitrator, and moderator for a multiplayer role-playing game. They are most common in co-operative games where other players work together and are less common in competitive games where other players battle one another.