Sisterhood of Karn The Sisterhood of Karn was a female society dedicated to protecting the Sacred Flame , which produced the Elixir of Life . They originally came from Gallifrey , but resided on the planet Karn . History . Prior to the Last Great Time War . The Sisterhood was a remnant of the Pythia ' s power . ( PROSE : " " ) The Great Mother of the Sisterhood and her High Priestess Cassandra , from the House of Jade Dreamers , plotted to destroy Rassilon ' s Foundry along with Lord Provost Tepesh and Lady Ouida from " the Committee of Three " . Tepesh and Ouida , who were also Great Vampire s , murdered Cassandra before all were killed by the automated sterilisation of the Foundry . ( AUDIO : " Zagreus " ) The Sisterhood entered into the Pact of Rassilon for protection under Gallifrey . They also fought against Morbius when he attempted to invade Karn . ( PROSE : " Warmonger " ) The Sisterhood manufactured their Elixir of Life under licence to produce Dr Solon ' s Special Morbius Lotion . They made one pot every hundred years . ( PROSE : " " ) When the Sacred Flame appeared to be dying , the Sisterhood suspected the Fourth Doctor of trying to steal the remaining Elixir , but later helped him defeat Morbius . In reality , the only thing wrong with the Flame was that centuries of ash and soot were finally beginning to clog the underground fissure that fed the flame natural gas . The Doctor easily solved the problem by dropping a simple firecracker down the shaft . ( TV : " The Brain of Morbius " ) Skagra learned the location of " The Worshipful and Ancient Law of Gallifrey " by capturing and torturing a member of the Sisterhood . He drugged her with synaptrol , an anti - telepath drug derived from the Lethe flower , and kidnapped her ; he then withheld food and water from her until she told him that the book was with Professor Chronotis in Cambridge . ( PROSE : " Shada " ) After Romana II became President of Gallifrey , she opened diplomatic relations with the Sisterhood . ( PROSE : " Lungbarrow " ) The Sisterhood were capable of teleportation using the Sacred Flame . They later tried to prevent Morbius ' resurrection ; failing to do this they saved the Eighth Doctor after he threw himself and Morbius into the core of Karn . ( AUDIO : " Sisters of the Flame " / " The Vengeance of Morbius " ) During the Last Great Time War . When the Eighth Doctor crashed on Karn and died in a spaceship crash , the Sisterhood recovered his body and used their Elixir to temporarily resurrect him . They were unable to bring him back permanently due to the severity of his injuries but instead offered to use their Elixir to control his regeneration so he could choose the form and personality he took . The Sisterhood explained that they were helping him due to owing him for the last time and because they believed that he was the only hope of stopping the Last Great Time War without destroying the universe . In the end , the Doctor agreed and with the Sisterhood ' s help , regenerated into his Warrior incarnation . ( TV : " The Night of the Doctor " ) Karn and the Sisterhood ultimately survived the Time War . ( WC : " Prologue " ) After the Last Great Time War . After meeting ( and abandoning ) a young Davros on the battlefields of Skaro , the Twelfth Doctor visited Ohila on Karn , hiding himself from the universe so effectively that no one could find him . While the Sisterhood gave him refuge , the servant of Davros known as the Colony Sarff visited Karn in its search for the Doctor . However , Ohila warned the visitor that the Doctor was not one to be trifled with , and when the Colony became angered and threatened the Sisterhood she informed Sarff that its powers were useless on Karn . Thwarted , the Colony departed , leaving Ohila with an ominous message for the Doctor — " Davros knows , Davros remembers . " ( TV : " The Magician ' s Apprentice " ) Seeing that the Doctor was deeply troubled by this , Ohila attempted to comfort him , and warned him against heeding the summons of his old foe , but the Doctor could not be dissuaded . After failing to change his mind about the meeting , Ohila agreed to deliver the Doctor ' s Confession dial to his oldest friend , the Master . The Doctor told her that he would stay a little while before going to meet his ancient enemy . ( WC : " Prologue " ) Some members of the Sisterhood visited Gallifrey on hearing the Twelfth Doctor had returned from the torture of his confession dial , Ohila citing the reason for her visit as " One so loves fireworks . " ( TV : " Hell Bent " )