Richard Lazarus Professor Richard Lazarus was a man who craved immortality . Biography . Childhood . Lazarus was only a child during World War II but had vivid memories of it . He hid in Southwark Cathedral during the London Blitz with others . He sat in the crypt , the living amongst the dead and feared death . His childhood home was destroyed in the bombing . Genetic manipulation . Lazarus built a Genetic Manipulation Device with financial backing from . It took him many years to complete , and he was seventy - six years old when he finished it . When interviewed on television , he spoke of how his experiment would " change what it means to be human . " The head of PR , Tish Jones , organised an unveiling of the experiment . He stepped into the machine when it was activated . Despite engineering faults , the machine worked , taking thirty years off his age . He stepped out a younger man . After effects . Unbeknownst to Richard , the process had activated dormant gene s in his DNA . They refused to settle down and he transformed into an alternate evolution of humanity which fed on human life energy . In this form he killed his associate , Sylvia Thaw , draining her of life . Lazarus then returned to human form . He needed still more for the mutation to stabilise , so he took Tish up to the roof , intending to drain her . The Tenth Doctor and Martha Jones interrupted them and ran from him as he again mutated . He chased them down to the main room where he drained another victim . The Doctor distracted him , leading him to a lab where he caused an explosion . This only angered Lazarus , who continued his pursuit . Martha and the Doctor hid within the Genetic Manipulation Device , knowing Lazarus would not want to damage it . Lazarus activated it but the Doctor altered it so that it let out a blast that incapacitated Lazarus . He changed back to human form and , seemingly dead , was taken away in an ambulance . Death and legacy . Lazarus had , however , survived the blast . He recovered and drained the two ambulance men with him . He then escaped the ambulance and hid in Southwark Cathedral . He chased Tish and Martha up to the bell tower , mutating again . While he was there , the Doctor used the amplified noise of the organ to confuse and injure Lazarus , mere seconds before Lazarus could drain Martha . He lost his balance , fell from the tower to his death and his corpse changed into his young human form , then into his old form . ( TV : " The Lazarus Experiment " ) The Tenth Doctor later saw him among many distorted illusions created by the Door . ( COMIC : " Destiny ' s Door " ) Undated events . At some point during the events of his mutation , he visited Penhaxico Two . ( COMIC : " Escape to Penhaxico " ) Personality . Lazarus ' main desire was to obtain immortality . This was motivated by his traumatic experiences as a child during World War II . He was willing to go to any lengths to obtain his ultimate goal , having worked his whole life on his machine . Once he mutated , this trait of his character only worsened , as he was more than willing to succumb to his hunger and feed off innocent people just to prolong his own life . When the Tenth Doctor told Lazarus about the burdens of a long lifespan such as a Time Lord ' s and the horror of seeing everyone he cared about die around him , Lazarus simply brushed it off and called it " a price worth paying " . Another prominent aspect of his personality was his womanising tendencies . Even when he was 76 years old , he flirted with Tish Jones , who originally viewed him as a repulsive man when he made such advances . It should be noted that all members of his staff appeared to be young women in their twenties . Once he was rejuvenated , he became more openly flirtatious and was seen having his picture taken with numerous young women around him . He would resort to womanising on two occasions before his death , the first with Lady Thaw ( where he utilised it in an argument they were having ) and Tish Jones ( only minutes later , showing he had essentially discarded Lady Thaw after killing her ) . However , in his mutated form , Lazarus outright discarded any adoration for women ( or , indeed , human beings ) , citing their slaughter to be a necessary sacrifice , even though their deaths achieved nothing but showing him to be so much of a monster . Lazarus was also incredibly vain , to the point of developing a God complex : after he had become younger , he developed the concept that he was immediately superior to everyone else . He payed no attention to the Tenth Doctor ' s warnings about the uncertainty of the machine ' s process and once he had transformed , he called his mutation " progress " . He even mockingly suggested to the Doctor that he would undergo the process three or four more times simply in order to deride him . In a successful attempt to provoke him and spare Martha ' s family , the Doctor called Lazarus " a vain old man who thought he could outsmart nature " and " a joke " , which actually was a completely accurate observation : Lazarus was too narcissistic and too callous to realise that his process had not only failed , but it had destroyed him . Lazarus was fairly sentimental , as evidenced by the way in which he remembered his childhood during the Blitz . However , this sentiment descended into his ambition even more , since he became obsessed with cheating death after the Blitz . Powers and abilities . After having stepped out of his machine , Lazarus soon mutated into a gigantic hideous creature that was actually an evolutionary throwback . Though this option was rejected by evolution for humanity millions of years ago , the Tenth Doctor stated that the potential was still there , locked away in humans ' genes , suggesting that human who underwent the same process would suffer the same mutation . In his mutated form , Lazarus displayed superhuman strength thanks to his massive size . He hurled a table at Leo Jones with such force that it knocked him out . Due to his extra limbs , he was also gifted with superhuman agility and dexterity . Despite being massive in size , he could easily fit through doors and even climb along walls and ceilings . He also demonstrated incredible durability and resistance to damage , surviving an enormous explosion set off by the Tenth Doctor without a scratch . A powerful blast of hypersonic soundwaves left him seemingly dead only for Lazarus to recover minutes later . He was finally killed when he fell from the top of the bell tower of Southwark Cathedral , dying upon impact . His most fearsome weapon was a massive tail similar to that of a scorpion . By stabbing a victim with the two pincers on the end , Lazarus could drain a human of all their life energy in seconds . This inevitably killed the victims , which were reduced to dessicated husks .