Ashildr Ashildr , who later began calling herself Me due to her immortality - related memory loss , was a Viking girl encountered by the Twelfth Doctor and Clara Oswald . After a battle with the Mire , Ashildr died , but she was resurrected by the Doctor via a Mire repair kit . As a result of this , Ashildr became immortal . She went on to live a long life , becoming very experienced and familiar with the universe and its various species in the process . Ultimately , she lived through the remainder of human history and to the end of time itself , and in the process , managed to outlive every other immortal in existence . Ashildr lived to the end of the universe , maintaining a reality bubble to keep her alive . She then boarded a TARDIS stolen by the Doctor , and watched silently as Clara wiped the Doctor ' s memories of ever travelling with her . She and Clara then took the Doctor to Nevada , disguising the TARDIS as an American diner where Clara pretended to be a waitress . After Clara realised that the Doctor ' s memories of her were fully gone , she and Ashildr left Earth to travel the universe . Biography . As Ashildr . Ashildr was the daughter of Einarr , a farmer in a 9th century Viking village . Ashildr greeted a group of Viking warriors when they returned from their journey with the Doctor and Clara in chains . Soon after their arrival , a figure claiming to be Odin appeared in the sky and invited the warriors to join him in " Valhalla " . Having been given half of the Doctor ' s sonic sunglasses by one of the warriors , and encouraged by Clara to use them , she was also taken to the Mire spaceship when undoing Clara ' s chains . Unable to save the warriors , who were killed for their testosterone and adrenalin , Ashildr confronted " Odin " to the point of declaring war on the Mire . She and Clara were returned to the village , where they were given one day to prepare for the Mire ' s return . When the Mire attacked , Ashildr was an integral part of the Doctor ' s plan to save the village , donning a Mire helmet and using her imagination to send false signals to the rest of the Mire , who viewed their surroundings via holograms . When " attacked " by a wooden dragon , the Mire believed the dragon to be real , and retreated when the Doctor threatened to share the footage which would ruin their reputation . Ashildr was killed in the process , but was resurrected by the Doctor altering a Mire repair kit to fix human physiology . He left another for her to give to whomever she chose , knowing that she would continually be fixed , thus losing the " ability " to die . The Doctor later realised that she was a human - Mire hybrid . ( TV : " The Girl Who Died " ) Immortality ' s burdens . Under the alias Lady Sherade , Ashildr caught the eye of the King of Samarkland and married him , telling him the story of how she met Sinbad and Ali - Baba under the alias Ash El Dir . ( PROSE : " The Arabian Knightmare " ) Using the alias Alys , Ashildr married Tomas and stayed with him for twenty years . Their relationship produced three children : Essie , Johann , and Rue . Essie was unexpected and Ashildr believed she did not want children until Essie was born , then she realised how much she loved her daughter . She decided to have two more children so that they could comfort one another one day when she would inevitably leave them to protect the secret of her immortality . On 9 August 1348 , Ashildr took her children and left their lives in France on a boat for Britain . She chose to leave Tomas because she feared his growing comments about how having three children in twenty years didn ' t appear to have changed her body and he would ask if her hair grew . During the voyage her children caught the Plague . She tried to decide which one of them to save with the second Mire medical patch , but ultimately decided to save none of them . ( PROSE : " The Triple Knife " ) She kept the pages in to remind her to never have any more offspring as they would all die eventually . During eight hundred years of immortality , Ashildr soon forgot her own name and even her life as a Viking . She began to pick up new names as her life went on , but each name died along those who knew her by it . She at some point decided to go by the name Me . As " Me " , she had no attachment to anything or anyone that she would eventually outlast . She took part in the Battle of Agincourt , declaring to be able to " fire six arrows in under a minute " . She began to write a journal of her life , though she ripped out pages when reading them as they were too hurtful to force herself to remember in the future . ( TV : " The Woman Who Lived " ) On one occasion , she fell in love with a man before leaving him . She returned long after to find him aged to senility , and was horrified as he considered her a ghost of a time long gone . Soon becoming bored of life , she turned to living a double life as a criminal , stealing the riches from wealthy people while also living as " Lady Me " with a servant , Clayton , whom she gradually became bored with . By this time she had become cold , detached and saw little meaning in life since by her point of view their lives were like smoke . She also became bitter at the Doctor for not taking her with him in his travels and leaving her to move through life . One day , Me found a Leonian named Leandro resting in her courtyard . He claimed to have crashed on Earth and they formed a partnership in order to retrieve the Eyes of Hades . The amulet would allow Leandro to leave Earth and he agreed to take Me with him . ( TV : " The Woman Who Lived " ) While committing a failed robbery on Mr Fanshawe and Lucie Fanshawe ( during which time she affected a convincing male voice as part of her disguise ) , Me encountered the Doctor again while he was searching for the Eyes of Hades . The Doctor didn ' t recognise her until she removed her mask and reverted to her original voice . The Doctor subsequently helped Me steal the Eyes of Hades from the Fanshawe household , initially not knowing about Me ' s partnership with Leandro . After the Doctor was introduced to Leandro , he learned of their plan to leave Earth by killing someone for a power source . Me was originally going to use her butler . She eventually settled on highwayman Sam Swift the Quick as the victim since he was sentenced to die anyway . After the portal was opened , Me realised that Leandro was lying and was using her so his brethren could invade Earth . Horrified by what she had done , Me used the second Mire kit to revive Sam Swift and close the portal , leading to Leandro being executed by the Leonians . She later had a drink with Sam and the Doctor . When she asked the Doctor if Sam was immortal now he replied that he wasn ' t sure . She promised to watch the Doctor for as long as he was alive in order to protect Earth from him . ( TV : " The Woman Who Lived " ) Life in the 21st century . " Me " lived into the 21st century . She appeared in the background of a selfie taken by Clara Oswald and Evie Hubbard , which Clara planned to show the Doctor . When she did , he noticed Ashildr in the background but did not say anything to Clara . ( TV : " The Woman Who Lived " ) Me became the mayor of an alien refugee camp hidden in the heart of London , for those who were desperate and destitute , without hope or a home . This camp was called the trap street . Later , to ensure the safety of the trap street , ( TV : " Face the Raven " ) she was convinced by the Time Lord s to trick the Doctor into being transported inside his confession dial . ( TV : " Hell Bent " ) She set up a plot where Rigsy " murdered " Anah , a Janus resident of the trap street , when actually she was placed inside a stasis chamber by Ashildr . She placed a chronolock on Rigsy , and was successful in luring the Doctor to the street , where Clara " stupidly " took the chronolock from Rigsy . Horrified by this turn of events , Me revealed she couldn ' t remove the chronolock – she had made a specific agreement with the Quantum Shade for Rigsy , and Clara had destroyed the deal , taking it out of Me ' s hands . Clara was killed by the Quantum Shade , and the Doctor was tricked into having a teleport bracelet attached to his wrist to teleport him away . As he left , the Doctor warned Me that Clara ' s pleas were meant to protect her and her people from the Doctor , and it would be a good idea for Me to stay out of his way . Me acknowledged this numbly . ( TV : " Face the Raven " ) At the end of the universe . Me was present at the very end of time , the last living being in the universe . To survive she created a bubble of reality among the ruins of the Cloisters on Gallifrey , passing the time watching the stars die while awaiting the Doctor and Clara ' s arrival . Five minutes before the final end of time , their stolen TARDIS appeared and Me knocked on the door . Me had set up a chess game , though she and the Doctor didn ' t play . She remarked that the dying stars were a beautiful sight ; when the Doctor said that it was sad , Me retorted that it was both , and the same was true of Clara ' s death , now a fixed point in time . She inquired about the Hybrid , which the Doctor accused her of being . Me countered that she was a human with a little bit of Mire , not a true hybrid . She then suggested that the Doctor might be half - human and thus he was the Hybrid . As the Doctor refuted that suggestion , Me offered her true theory : the Hybrid wasn ' t a single individual , but a Time Lord and his human companion , so alike that they constantly push each other into more and more catastrophic actions . The Doctor revealed he had come to the same conclusion and was thus planning to erase all Clara ' s memories of him and leave her someplace safe . Me then entered the Doctor ' s stolen TARDIS and witnessed his final confrontation with Clara in silence . ( TV : " Hell Bent " ) Travelling with Clara . Me assisted Clara in her attempt to make sure the Doctor ' s memory of her was truly gone - and perhaps even restore it , if possible - but remained in the new TARDIS so as not to arouse suspicion . When Clara concluded that the Doctor ' s key memories of her were gone and could not be restored , she and Me left aboard the new TARDIS . Me reported that she was unable to get the chameleon circuit to work , so the TARDIS was stuck looking like a 20th - century American diner . Clara approved , stating the situation was awesome . Clara then declared her intention to return to Gallifrey to face her death , but noted that since time didn ' t appear to be in any immediate danger and she was now ageless , there wouldn ' t be any harm in taking the long way back . Clara then activated the TARDIS , taking Me with her to explore time and space . ( TV : " Hell Bent " ) Abilities . Due to the Mire technology within her , Ashildr was functionally immortal , which meant she did not age , injuries and illness that would have killed a normal human would heal , and she had a potentially infinite lifespan . There were limitations : according to the Doctor she was not totally indestructible and it was possible for her to be injured sufficiently enough to die . She also suffered from memory loss over time , as her human brain was incapable of storing millennia ' s worth of experiences . For a time , she relied on volumes of written diaries to remind her of events from the past . ( TV : " The Woman Who Lived " ) During her time as mayor of the trap street in London , Me had a mental link with an agent of the Quantum Shade that manifested itself as an animated tattoo on her chest , although her agreement with the entity had strict rules and she was unable to prevent it from killing Clara . ( TV : " Face the Raven " )