There are two Guardians of the Universe.The While Guardian who is the balance for the side of good and the Black Guardian who is the balance for the side of evil or darkness. The Guardians first made their appearance in the 6 story's of the 4th Doctor's story arc "The Key To Time". At the end of the story arc, the Doctor having foiled the Black Guardian has made an enemy of him. The Doctor then attached a randomiser to the Tardis control panel so the Tardis would travel to different places without the Black Guardian being able to track him down to met out his revenge. The Black Guardian was played by the late Valentine Dyall May 7th 1908 - June 24th 1985.