The Monks The Monks were an alien race who used a virtual simulation of life on Earth in order to plan an invasion . Virtual constructs included simulations of the Twelfth Doctor , Nardole and Bill Potts . ( TV : " Extremis " ) They were also able to see into the future through their simulation , and vowed to " protect " the Earth from the devastation they foresaw would occur in one year . However , they required genuine consent from people with power , and were able to sense if their consent was true or they were acting out of fear or strategy . If their consent was not pure , the person would immediately be disintegrated . ( TV : " The Pyramid at the End of the World " ) It was clear that the Monks showed no mercy for the human race in any way , and sought to control the Earth and humanity itself . They had no problems instantly killing people , and on multiple occasions threatened the Doctor himself . There was no clear hierarchy within the species , but it appeared that few Monks spoke while the rest remained silent . There would also be one Monk whose job would be to feed the invaded population falsehoods about their personal history . The Monks preferred to only conquer through the consent of the inhabitants and not force . When their hold on Earth was broken , the Monks retreated without a fight rather than using force to take back the planet despite possessing superior technology that could ' ve given them an edge . ( TV : " The Lie of the Land " ) Biology . The Monks chose their particular appearance on Earth to resemble human corpse s , due to seeing humans as corpses . ( TV : " The Pyramid at the End of the World " ) As a result , they had greyish - blue skin , pointed ear s and long finge rs . They typically wore robe s and cowl s with various shades of red , hence the name given to them . ( TV : " Extremis " ) They were apparently shapeshifter s , capable of choosing external appearance at will . ( TV : " The Pyramid at the End of the World " ) They spoke with a snarling , whispering voice , and their mouths did not move in sync with their voices . They typically moved quite slowly , and walked with their heads down and their hands together . They were able to sense the purity of one ' s consent simply by placing their hand over one ' s chest . If their consent was not pure , then the Monks were able to disintegrate them . ( TV : " The Pyramid at the End of the World " ) They were able to shoot out lightning from their hands , as well as make shields from this energy . However , they weren ' t invulnerable and gunfire that penetrated their shields could kill them . ( TV : " The Lie of the Land " ) Technology . The Monks had extremely advanced technology . One of their notable achievements was a computer simulation of the entire planet Earth in which they ran scenarios and practiced and perfected their invasion strategy , and also in order to assess the strengths and weaknesses of humanity . However , their simulation was too perfect . The simulations of real people that were part of the program were capable of gaining sentience . Once they realised the truth that they were nothing more than a program , they would choose to kill themselves rather than be constantly used and abused by the Monks . ( TV : " Extremis " ) They managed to make a 5 , 000 - year - old pyramid appear out of nowhere between the three largest armies in the world by the 21st century - America , Russia and China . This pyramid , called the Cathedral ( TV : " The Lie of the Land " ) was their base of operations on Earth and housed technology which enabled them to see into the future of their virtual Earth , as well as their spaceship on and off Earth . . They were also able to use threads from their simulation of Earth to see into the future , and predicted a World War III - like event where all human life would be wiped out in one year . They were able to spy on the human race through CCTV cameras , and were also able to hack into the technology of normal citizens of Earth , such as mobile phones or watches , and change the time to issue warnings about the safety of the Earth . It was later revealed the time changed in accordance with activities that unfurled within a science lab in Yorkshire when a scientist accidentally misplaced a decimal point and inserted 118 . 9 instead of 11 . 89 into the computer , killing their research immediately . The Doctor said that this event was going to ' blow up in their faces ' and was the reason for the state of Earth seen by the Monks in one year . Also , the Monks could hijack vehicles and other technology and appeared to be able to teleport themselves into areas such as planes . ( TV : " The Pyramid at the End of the World , The Lie of the Land " ) After the Monks get the consent they wish for to invade , they erect statues in most major areas in order to broadcast lies about the invaded planet ' s past . In the Cathedral , a Monk would be wired to what the Doctor called " Fake News Central " which they would broadcast the lies using the brainwaves of whoever gave their consent to invade the world . ( TV : " The Lie of the Land " ) History . For millennia , the Monks invade planets by studying them through the Shadow World , finding someone in power to ask them for help out of " love " to stop some form of a disaster . Once the person consents to the Monks help , they form a link with the person who becomes their " lynchpin " through who they broadcast a revised version of the planet ' s history where the Monks have been there since the beginning . The psychic link gets passed through the bloodline of the Monks " lynchpin " and the link only ends if the " lynchpin " dies or the bloodline ends . ( TV : " The Lie of the Land " ) At an unknown point in time , an incarnation of the Master encountered a planet ruled by the Monks . The Master ended the Monks hold on the planet by throwing their " lynchpin " , a young girl , into a volcano . ( TV : " The Lie of the Land " ) The Monks eventually started going after Earth as a potential new planet to rule . The simulated version of the Twelfth Doctor eventually discovered the truth and emailed a recording of the Monks simulation to the real Twelfth Doctor through the sonic sunglasses , warning him of the threat . ( TV : " Extremis " ) After discovering the accidental creation of a world - ending bacteria , the Monks predicted a timeline where the Earth would be dead within a year and landed the Cathedral in a potential war zone in Turmezistan . The Monks showed a vision of the future they predicted to the gathered world leaders , including the Doctor as the President of Earth and offered to stop the event if the leaders consented out of " love " . Each leader attempted to consent out of fear or strategy and were incinerated , but the Doctor managed to stop the bacteria on his own . Due to the Doctor ' s blind ness , he would die in the explosion he set so Bill Potts consented in exchange for the Monks restoring the Doctor ' s sight . ( TV : " The Pyramid at the End of the World " ) Over the next six months , the Monks quietly took over Earth , using Bill as their " lynchpin " and giant statues of themselves as transmitters to boost the signal of an alternate version of history where the Monks have always been on Earth and ruled the human race . The Monks locked the Doctor up in a prison ship , but he was eventually able to deprogram his guards and with the help of Nardole , recruit Bill to end the Monks rule of Earth . After learning from Missy that wiping Bill ' s mind would be the most effective way to end the Monks rule , the Doctor led an assault on the Cathedral to find the Monks device that broadcasted the fake version of history and overwhelm it with the truth . After linking with the Monk controlling the device nearly killed the Doctor , Bill tried in an attempt to fry her brain so the Monks could no longer use her as Missy suggested . This failed at first as the Monk instead infected Bill ' s memories and used them to solidify the Monks control over the human race , but when Bill started broadcasting memories of the version of her mother she made up in her head , the Monk was unable to touch these pure memories . Ultimately , Bill ' s efforts broke the link and the Monks lost control of humanity . With humanity turning on them , the Monks retreated from the Earth . Afterwards , humanity showed no memory of the Monks six month rule of them and the Doctor explained to Bill that the Monks erased themselves from human history . ( TV : " The Lie of the Land " )