Now weve already mentioned the Guardians of Time in this post, so why not one of their principal members, who also happens to have a hatred of the Doctor. The Black Guardian, also known as the Guardian of Darkness and Choas, was the personification of the forces opposed to the powers of light, which were naturally embodied by the White Guardian. He represents all that is evil and chaotic in the universe and is constantly looking to tip the scales in his own favour, mostly through intermediaries or his follower Wrack. We met him when the White Guardian sent the Fifth Doctor to travel around the universe and collect the powerful Key to Time, which the Black Guardian tried to trick into his own possession in order to boost his own power to unfathomable levels. The Doctor saw his plan and instead dispersed the key throughout the universe instead of letting the Black Guardian become too powerful, with the villain vowing vengeance as a result. When the Doctor beat him again during the events of Mawdyrn Undead, the White Guardian warned that his opposite would surely try to even the score at some point. That vengeance is yet to come about, but its definitely time it did.
