Dalek Thay Dalek Thay was a member of the Cult of Skaro . Biography . Origins . Thay was the Commandant of Station Alpha and was chosen to be part of the Cult of Skaro along with Dalek Jast , Dalek Caan and their leader , Dalek Sec . The purpose of the cult was to " think like the enemy " and come up with novel and unorthodox methods of furthering the Dalek s ' cause in a predicted war that was coming . It was their leader , Dalek Sec , who began using their initiative to defeat enemies . ( PROSE : " Birth of a Legend " ) During the Last Great Time War the cult escaped the carnage by hiding between realities in a Void ship , along with the Genesis Ark , which contained an army of imprisoned Daleks . ( TV : " Doomsday " ) The Battle of Canary Wharf . Thay was the first Dalek to encounter the Cybermen during the Battle of Canary Wharf in 2007 . He was tricked into identifying himself by the Cybermen after both sides refused to " identify first " . When the Cybermen proposed an alliance , Thay denied their request , opened fire on them , and returned to the sphere chamber . Thay aided in the awakening process and fought in the following battles against the Cybermen and Torchwood staff to protect the Genesis ark until it opened . Thay spoke in a slightly low - pitched voice with an unusual nasal croak . ( TV : " Doomsday " ) The Final Experiment . In 1930 in New York City , Thay originally had strong feelings against the Final Experiment , even to the point of countering Dalek Sec ' s orders , claiming that it was against the Dalek ideology of racial purity , but eventually conceded that it was necessary for survival . To complete the Empire State Building before the gamma strike hit Earth , three of the back plates of Thay ' s casing were removed and attached to the building ' s mast , being replaced with iron as the Dalekanium of the plates was required to attract the gamma strike . ( TV : " Daleks in Manhattan " ) When the Doctor witnessed Dalek Sec become a human - Dalek and freed multiple prisoners , Thay , Caan and the pig slave s tried to recapture them . Failing to do so , Caan ordered the slaves to return to base . Once alone , Caan asked Thay ' s opinion of Sec . Thay stated the cult was created to follow Sec but confirmed he had doubts . When Sec sent Jast , Caan and the pig slaves to attack Hooverville , Thay stayed with his leader to oversee the assault via a visual link and noted Sec ' s reaction to Solomon ' s extermination and refusal to allow the Doctor be killed by Dalek Caan . Thay later demanded an explanation as to why Sec had spared the Doctor , Sec replied that the Doctor was a genius and the future of the Daleks depended on him . During the creation of the human - Dalek race , Thay rebelled against Sec and the Doctor with Jast and Caan by overriding the gene - feed with pure Dalek gene When the Doctor discovered this , the cult ' s remaining pure members revealed their true intentions and threatened to kill the Time Lord if he didn ' t step away from the controls . When Sec ordered the cult to stand down , Jast stated that the Doctor was an enemy of the Daleks and Sec was designated likewise . Thay then justified Jast ' s statement that Sec had lost his authority by stating he was no longer Dalek . After the brief argument , Thay ordered the pig slaves to restrain Dalek Sec and the Doctor while the cult monitored the gamma strike for the final experiment . When the gamma radiation finally hit and awakened the army of hybrids , Thay proudly declared the accomplishment to his colleagues . Once fully awakened , the cult informed the new species of their plans and armed them with Dalek weaponry adapted from Tommy guns . As the new soldiers spread under Manhattan using the sewer system , Caan pronounced himself the new commander , and ordered that he be connected to the military computer , despite Sec ' s protests that the position was reserved for him ; Thay simply stated that his former leader was no longer fit . Thay and Jast were then dispatched to the theatre to face the Time Lord . While confronting the Doctor in the theatre , Thay claimed the Time Lord had to die and was about to fire when Sec , now imprisoned with his chains on Thay ' s Manipulator arm , threw himself in front of Thay ' s death ray causing his extermination . After the Doctor explained that the Dalek - humans weren ' t Daleks and that his Time Lord DNA was mixed with their Dalek and human DNA in the " Final Experiment " , the Dalek - humans questioned orders and revolted against their Dalek masters . Thay immediately opened fire on the hybrids claiming , " If they will not obey then they must die ! " Although Thay and Jast exterminated many Dalek - humans in the process , the resulting fire fight destroyed them both . ( TV : " Evolution of the Daleks " ) Personality . Dalek Thay had the second - lowest - pitched voice of the Cult , with a nasal croak . Thay was the least reserved of the Cult and would often voice his opinion to his leader . He would often taunt his opponents with Dalek ideals and always seemed to want the Dalek race to be " pure " , as demonstrated during the Final Experiment . ( TV : " Evolution of the Daleks " ) During the experiment , he protested to Sec ' s bonding with Mr Diagoras ( TV : " Daleks in Manhattan " ) and later protested when the Doctor and Sec spoke of how Davros was wrong to strip the Daleks of emotions , and that it would be better to no longer be the " supreme beings " . He seemed very loyal to Dalek Sec until his hybridisation , and to Dalek Caan when they revolted against Dalek Sec . He did not hesitate to exterminate anyone who stood in their way , including Sec himself although this was an accident . ( TV : " Evolution of the Daleks " ) Other information . Dalek Thay , as with all Daleks that originated from the Last Great Time War , possessed markings below his eyepiece to identify him . ( TV : " Doomsday " ) . Dalek Thay was the first named out of the cult by Dalek Sec , And was the first one to name himself to the Tenth Doctor . Dalek Thay killed Dalek Sec in his human hybrid form although he was intending to kill the Tenth Doctor and Sec jumped in the line of fire . He was the second member of the Cult of Skaro by fighting the Human Daleks .