The Fourth Doctor (Tom Baker) first encountered Davros (Michael Wisher) in "Genesis of the Daleks" when he and his companions were sent to Skaro to avert the creation of the Daleks. As chief scientist of the Kaleds and leader of their elite scientific division, Davros devised new military strategies in order to win his people's thousand-year war against the Thal race that also occupies Skaro. When Davros learned his people were evolving from exposure to nuclear and biological weapons used in the war, he artificially accelerates the process to his design and stores the resulting tentacle creatures in tank-like "Mark III travel machines" partly based on the design of his wheelchair. He later names these creatures "Daleks", an anagram of Kaleds.