Keeper of the Matrix
The Keeper of the Matrix, formerly known as the Coordinator of the Matrix (PROSE: The Eight Doctors) and also called the Keeper of the Record of Time, (PROSE: Mindwarp) was the Time Lord who watched over the Matrix and was in full charge of it. The Keeper kept the Key of Rassilon, the only key to the Matrix, on his person at all times. They were to keep the Matrix in good repair and make any necessary adjustments. (TV: The Ultimate Foe)
Engin served as Coordinator of the Matrix for quite some time. (TV: The Deadly Assassin) He was replaced by Zon after Niroc became President, for whom the title was changed to "Keeper" rather than "Coordinator". Engin retired and became an Independent on the High Council. (PROSE: The Eight Doctors)
At the conclusion of the Sixth Doctor's trial, Zon was taken over by the Valeyard. (TV: The Ultimate Foe)
Engin was once again the Keeper by the time of the Last Great Time War. (COMIC: Sky Jacks)
Councillor Volstrom consulted the the Keeper during the Doom Coalition crisis. (AUDIO: Songs of Love)
