The Master of Races was an imp that appeared to start a race when a player blows a starting horn. Nearby players wearing racing boots were unable to move while he announced "Ready! Set! Go!". When he said "ready", the flame on his torch was red. When he said "set", the flame turned yellow. When he said "go", the flame turned green, and players could start running.
Players could buy a starting horn and racing boots from Faruq in Al Kharid, whose stall is near the silk trader. The Master of Races could teleport to virtually any imaginable location, even those not of Gielinor, such as the Runecrafting Guild's plane and the Land of Snow, as long as the player had the horn on them.
It could not be summoned if another Master was nearby, and gave the message: "Your race starter cannot appear near another." This could cause confusion among a group if multiple people attempt to blow the horn, and could even be used maliciously to delay a race.
The Master of Races, along with the starting horn, was removed from RuneScape on 8 December 2014 to prevent gambling.