Black Guardian The Black Guardian , also known as the Guardian of Darkness and Chaos , was an anthropomorphic personification of the forces opposed to the powers of light , as embodied by the White Guardian . With the White Guardian and four others , he was part of the Six - Fold God known as the Guardians of Time . ( PROSE : " The Quantum Archangel " ) An infinitely powerful universal force of chaos , ( AUDIO : " The Trouble with Drax " ) he was the representative of all that was evil and chaotic in the universe , balanced only against the White Guardian , ( AUDIO : " The Dalek Contract " ) although another " interface " stated he was not evil but merely the opposite of law , representing both chaos and freedom . ( AUDIO : " The Destroyer of Delights " ) Powers . The Black Guardian was the embodiment of chaos in time . Like all Guardians , he was only as powerful as his element in the universe . He was able to change his appearance at will , enter the Doctor ' s TARDIS , and channel his power of destruction to his follower Wrack . He appreciated creatures with random flaws and perfections , such as vampire s . While he was powerful , theoretically , he could do much more damage with the Key to Time . In addition , he was unable to enter the Doctor ' s TARDIS when its defences were activated ( TV : " The Armageddon Factor " ) and was additionally dispersed by time differential , the Key to Time being broken , and Enlightenment . ( TV : " Mawdryn Undead " , " The Armageddon Factor " , " Enlightenment " ) The Black Guardian was the most powerful at the end of the universe where his counterpart could interfere the least , and he was able to follow the Doctor through time and space , seeing his adventures against the Wizard of Avalon , the Animus , Ruath , and the Timewyrm . He could only contact lower primates ( like human s and Trions ) when their minds were knocked into altered states . ( PROSE : " The Well - Mannered War " ) He seemed able to hypnotise people and appear in their dreams like Eternal s , but unlike them he could not telepathically read minds . Additionally he possessed mechanical knowledge of the TARDIS and Terminus , instructing Turlough how to operate controls and to sabotage the TARDIS console . ( TV : " Mawdryn Undead " , " Terminus " ) History . Vampires . The Fifth Doctor theorised that the Black Guardian played some part in the concept of vampires , seeing their potential as creatures of chaos , and somehow being responsible for the law of vampires not becoming " true " vampires until a full moon . ( PROSE : " Goth Opera " ) Prometheus and the Millennium War . The Black Guardian , collectively with the other Guardians , removed Prometheus from existence and imprisoned Kronos , then known as Avatar , in the crystal of Kronos and threw it into the Time Vortex . They later answered the call of the survivors of the Millennium War and granted their request to erase their memory of the war . ( PROSE : " The Quantum Archangel " ) The first quest for the Key to Time . The White Guardian sent the Fourth Doctor and Romana I on a quest to find the six segments of the Key to Time , transmuted into a variety of forms and scattered across time and space . He warned them of the Black Guardian who would try to prevent the assembly of the Key . ( TV : " The Ribos Operation " ) The sixth and final segment took the form of a living being , Princess Astra of Atrios . The Black Guardian used the Shadow to try to prevent the Doctor and Romana from re - assembling the Key . After the Doctor defeated the Shadow and re - assembled the Key , the Black Guardian posed as the White Guardian and asked for the Key . Observing the Black Guardian ' s casual indifference to the life of Princess Astra , the Doctor saw through this ruse and scattered the Key through time instead . The Black Guardian swore revenge on the Doctor . ( TV : " The Armageddon Factor " ) The revenge . To evade the Black Guardian ' s revenge , the Doctor fitted the TARDIS with a randomiser to prevent the Guardian from knowing where they would materialise next . ( TV : " Destiny of the Daleks " ) While he and Romana I took up residence in a London townhouse in 1929 , K9 programmed the TARDIS to visit approximately 1 , 000 planets , which took about a month , in order to lead the Guardian on a false chase , ( AUDIO : " The Auntie Matter " ) although the Black Guardian later claimed this was a failed endeavour . The Black Guardian created the construct known as Cuthbert , a " self - made " man because his timeline was a temporal paradox , whereby he created his own existence . As such , his company the Conglomerate was so entwined with history that to destroy it would cause chaos throughout the universe . Using the alias " Mr . Edge , " and believing the Doctor must follow a moral code , he tried to trick the Doctor into shooting Cuthbert and killing him , preventing him from influencing history . The Doctor caught on , however , because Edge couldn ' t kill Cuthbert himself , and refused to stop Cuthbert from firing on a Salonu ship . Although he missed , the ship still crashed on 6th century Earth , and history continued , foiling the Guardian . ( AUDIO : " Casualties of Time " ) A second attempt at revenge occurred when he lured the Doctor and Romana to Barclow . He engineered the war between the Human s and the Chelonian s as well as manipulating Galatea to create the concept of consular privilege to allow K9 Mark II to become a presidential candidate . Menlove Stokes was used in the plans to destroy the femdroids ' controls and set the TARDIS ' controls to take them to Dellah in the 26th century . He bargained on the Doctor ' s rash decisions to set the Darkness on the universe when the Doctor dematerialised the TARDIS , planning to send them into deep space . The Doctor foiled his plans again by using the emergency unit to take himself out of time and space . ( PROSE : " The Well - Mannered War " ) A different method . Eventually , the Doctor grew sick of running from the Guardian and removed the randomiser , ( TV : " The Leisure Hive " ) the Guardian ' s wrath no longer worrying him , and the Doctor would spend a significantly long grace period before he squared off with him again . ( TV : " Meglos " to TV : " Snakedance " ) . Later , however , the Fifth Doctor would pilot the TARDIS to more enjoyable and relaxing destinations , worrying that the Black Guardian would track him down more easily . Incidentally , the Guardian had some part in organising Ruath and Yarven ' s scheme to restore Gallifrey to power in an era after it had ceased to exist , turning human ity into vampire s and spreading out across the universe . When they were defeated by the Doctor , he met with the White Guardian on Gallifrey and confided that he would need a different method to defeat the Doctor . ( PROSE : " Goth Opera " ) Turlough ' s assistance . The Black Guardian appeared to Turlough , a young Trion exiled to Earth . He promised Turlough that , if he killed the Fifth Doctor , he would return Turlough to his home . He gave Turlough a small crystal to communicate with him . Turlough ended up joining the Doctor , Tegan and Nyssa in the TARDIS , still at least partly determined to carry out his mission . ( TV : " Mawdryn Undead " ) As he grew fonder of the Doctor , Turlough began to rebel against the Black Guardian , wishing to back out of the bargain . The Black Guardian still convinced Turlough to sabotage the Doctor ' s TARDIS . ( TV : " Terminus " ) The Doctor and his companions received a warning from the White Guardian about the Black Guardian . They then found themselves in the midst of a contest for Enlightenment , symbolised by a crystal of unknown powers and great value . It was much sought after by the amoral Eternal s , who vied for it by racing sailing ships across the Solar System . The Black Guardian hoped that , with such a prize , the Eternals might wreak havoc throughout the universe . Instead , the Doctor and Turlough won the race . The Doctor refused Enlightenment , offering it instead to Turlough . The Black Guardian told Turlough that , to get the crystal , he must kill the Doctor . Turlough refused and threw the crystal at the Black Guardian , who vanished in a burst of flames . However , the White Guardian said the Black Guardian would exist as long as he did , until neither were needed any longer . ( TV : " Enlightenment " ) The second quest for the Key to Time . The Black Guardian rescued the Fifth Doctor and Amy from an Ice Warrior ship which was plunging into a sun . According to Amy , he was not meant to get involved in their search as the Grace told her . ( AUDIO : " The Judgement of Isskar " ) After that encounter , the Guardian took them to many places but they could not find the fifth segment . The Doctor realised the Guardian was being methodical in his search ; they could find the fifth segment by being heedless of order , their destination controlled by chaos . The Guardian sent the Doctor and Amy on their way and followed them . In 9th century Sudan , he inserted himself into the time stream and became part of the events . As Lord Cassim , he evaded taxes to fix the Djinni ' s warp manifold , which needed gold , ( although platinum or plutonium would have been quicker ) to create the orium needed . This was the fifth segment of the Key to Time . This evasion brought the Legate of the Caliph , the embodiment of law in the region , to collect the tax . In the confusing welter of events , the Doctor and Amy were able to escape with the Key . ( AUDIO : " The Destroyer of Delights " ) Stranded in 9th century Sudan , he was a shadow of his former self , unable to become what he once was . When the Doctor became trapped on the Teuthoidian ship , he heard a voice on intra - ship communications which he thought was Romana II ' s and sent a telepathic communication to her ' answer phone ' . The voice was President Astra ' s , a double of Romana . Romana received the Doctor ' s answer and found the TARDIS in hyperspace . The TARDIS took her to some of its recent destinations , Mars and 9th century Sudan , where she found the Black Guardian , who led her to believe that he knew where the Doctor was . By the time she realised this wasn ' t true it was too late . He had rejuvenated with the power of the sixth segment : Romana herself . Trying to achieve his final goal , the Black Guardian used the gathered freedom fighters to stop the White Guardian ' s Teuthoidian horde from getting the Key , locking the two Guardians in opposing balance once again . At that moment the Grace reappeared and sent the two of them back to howling void , to continue their eternal struggle . ( AUDIO : " The Chaos Pool " ) The third quest for the Key to Time . The Black Guardian created an alternate timeline in which the First Doctor had never left Gallifrey , and was now Lord President . However , it also meant that countless aliens had invaded Earth in absence of the Doctor stopping them . The White Guardian sent them on a quest once more for the Key to Time , which could restore the natural timeline . ( COMIC : " Time & Time Again " )