Evil Evil was the concept or force perceived as being the opposite of what was good , both of them being part of moral duality . However , like good , evil could be perceived differently from conflicting vantage points ; evil was , according to the Seventh Doctor , a matter of perspective . ( PROSE : " Utopia " ) As such , the Seventh Doctor claimed evil had no name , ( TV : " The Curse of Fenric " ) and the Twelfth Doctor later asserted that " hardly anything [ was ] evil , but most things [ were ] hungry . " ( TV : " The Pilot " ) In the distant past , the Grey Man ' s people imposed duality onto the first humanoid s to evolve , resulting in them destroying themselves in chemical warfare . The Grey Man later created Cathedral as a metacultural engine that introduced " greyness " and " doubt " into the universe . ( PROSE : " Falls the Shadow " ) At the end of the Thousand Year War , Ronson told the Fourth Doctor that the Scientific Elite believed Davros had changed the nature of their research to something immoral and evil , which later resulted in the creation of the Daleks . ( TV : " Genesis of the Daleks " ) The First Doctor , in his first encounter with the Dalek s , called their plan to destroy the Thal s as " senseless , evil killing . " ( TV : " The Daleks " ) The Daleks , in fact , according to Bernice Summerfield , were " the most evil race the universe ever came up with " . ( AUDIO : " The Lights of Skaro " ) The Time Lord s did not believe in nor give much thought to the concepts of good and evil , but the Doctor had always maintained that evil was an actual force . ( PROSE : " Strange England " , AUDIO : " The Guardians of Prophecy " , COMIC : " A Groatsworth of Wit " ) When he was first put on trial , the Second Doctor used a Thought Channel to justify his interference in the universe by showing the Time Lord tribunal some of the evils he ' d fought , including the Quark s , the Robot Yeti , the Ice Warrior s , the Cybermen , and the Daleks . ( TV : " The War Games " ) In his travels he met many " embodiments " of evil , including the Black Guardian , ( TV : " The Armageddon Factor " ) the Mara , ( TV : " Snakedance " ) Malador , ( AUDIO : " The Guardians of Prophecy " ) , the Beast ( TV : " The Impossible Planet " ) and Fenric , whom the Doctor told Ace was one of two forces , only good and evil , that existed before the beginning of all time and space . ( TV : " The Curse of Fenric " ) The Ninth Doctor described the Shadey s as " something evil , " mentioning to Rose Tyler that " some people don ' t believe in evil . . . They say it ' s all subjective . No absolutes , " and as a rebuttal to this , he told Rose to " take a look " at the Shadeys . ( COMIC : " A Groatsworth of Wit " ) The Fifth Doctor believed that , considering its nature , the one thing evil could never face was itself , and utilised this principal to trap the Mara in a circle of mirrors and banish it from Deva Loka . ( TV : " Kinda " ) The Eighth Doctor called the Master " pure evil " . ( TV : " Doctor Who " ) The First Doctor declared that he opposed everything the Doctor held dear . ( AUDIO : " The Destination Wars " ) The Fourth Doctor referred to the Master as the " quintessence of evil " , ( TV : " The Deadly Assassin " ) while the Third Doctor described him as " the personification of evil " . ( TV : " The Sea Devils " ) Borusa told the Master that he was " one of the most evil and corrupt beings [ that ] Time Lord race [ had ] ever produced . " ( TV : " The Five Doctors " ) Even when Melanie Bush told him he was " utterly evil , " the Master replied , " thank you . " The Master later took offence to the idea of her having " gone good " . ( TV : " The Magician ' s Apprentice " ) In truth , anyone was capable of both good and evil , as the Master pointed out when he revealed to the Sixth Doctor that the Valeyard was a future version of him : While the Doctor often tried to be a force for good , ( TV : " Into the Dalek " ) his methods could be seen as evil , causing other races to raise arms in fear against him , ( TV : " A Good Man Goes to War " ) with an alliance including several of his enemies imprisoning him in an attempt to prevent the end of the universe . ( TV : " The Pandorica Opens " ) Several individuals considered the Doctor ' s good to be their evil , including Sutekh ( TV : " Pyramids of Mars " ) and the Black Guardian . ( TV : " Mawdryn Undead " ) Behind the scenes . " The Universal Databank " identified six types of evil which the Doctor has fought against . These were as follows :