The King's Demons is the sixth and final serial of the 20th season of the British science fiction television series Doctor Who, which was originally broadcast on BBC1 on 15 and 16 March 1983. This serial introduced Kamelion, voiced by Gerald Flood, as a companion. The serial is set in an English castle in 1215. In the serial, the alien time traveller the Master (Anthony Ainley) uses the robot Kamelion to imitate King John of England as part of the Master's plot to have the real King John overthrown and thus prevent the signing of Magna Carta.