However , in 1975 , Terry Nation revised the Daleks ' origins in Genesis of the Daleks , where the Dals were now called Kaleds ( of which Daleks is an anagram ) , and the Dalek design was attributed to one man , the crippled Kaled chief scientist Davros . In 1975 , Terry Nation revised the Daleks ' origins in Genesis of the Daleks , where the Dals were now called Kaleds ( of which `` Daleks '' is an anagram ) , and the Dalek design was attributed to one man , the crippled Kaled chief scientist and evil genius , Davros .