White Guardian The White Guardian , more accurately called the Guardian of Light in Time ( TV : " The Stones of Blood " ) , was the anthropomorphic personification of order and good in the same way that his opposite , the Black Guardian , embodied evil and chaos . However , different interfaces of the Guardians held different perspectives , with the Black Guardian later claiming to represent freedom while the White Guardian embodied domination . The Fifth Doctor even criticised him as the lesser of two evils , embodying the letter of the law rather than the spirit . ( AUDIO : " The Destroyer of Delights " ) Biography . Originating in the universe before N - Space , ( PROSE : " Divided Loyalties " ) the White Guardian was one of six beings , the Six - Fold God , that were at the pinnacle of reality . ( PROSE : " The Quantum Archangel " ) The White Guardian sent the Fourth Doctor and Romana I on a quest to find the six segments of the Key to Time , changed into a variety of forms and scattered across time and space . Assembling them , he said , would allow the restoration of balance and order by freezing all time for just a moment . He warned them of the Black Guardian , who also sought the Key . ( TV : " The Ribos Operation " ) After they had assembled the first two segments , he warned them of the Black Guardian again , as a disembodied voice . ( TV : " The Stones of Blood " ) The White Guardian and the Black Guardian offered Enlightenment , symbolised by a crystal of unknown powers and great value , as a prize to the winner of a space race undertaken by Eternal s . Turlough threw the crystal at the Black Guardian , who vanished in a burst of flames . The White Guardian explained that the Black Guardian would exist as long as he did , until neither was needed any longer . ( TV : " Enlightenment " ) On another quest to find the Key to Time , the Fifth Doctor and Abby found him in 9th century Sudan , crammed in " a measly number of dimensions small enough to count on one hand , a human hand " ( as he said ) . He posed as the Legate of the Caliph , the embodiment of law in that era , collecting taxes and punishing tax evaders such as Lord Cassim . He was only in Sudan after he followed the TARDIS there . This was Order ' s way of finding the Fifth Segment of the Key to Time . His adversary and he did not trust each other to carry out the Doctor ' s orders , and watched each other as they worked . When the Doctor left the Sudan , he was stranded there , waiting for the universe to end . ( AUDIO : " The Destroyer of Delights " ) He remained there for so long he forgot who he was . Eventually , Zara found him and took him to Atrios , where he became Professor Lydel , the scientific adviser for Princess Astra ' s mission to the Chaos Pool . Thanks to Amy and the Doctor arriving , he came in contact with the segments of the Key , and was rejuvenated . He tried to take the Key from the Doctor when he assembled it , using the Teuthoidian ' s army , which happened to be on Chaos . He failed , and was returned to the Howling Void and his eternal struggle with the Black Guardian by the Grace . ( AUDIO : " The Chaos Pool " ) The White Guardian later sent the Seventh Doctor , Ace and Benny on a quest to find the six segments of the Key to Time , scattered across the Doctor ' s personal timeline when he last disassembled it . ( COMIC : " Time & Time Again " )