Muller was a genius in the field of cybernetics, taught at an early age by Ensor. This tuition instilled the driven pace at which Muller conducted his work for the robot development cartel on Pharos. He created an android remarkable for its kind, which could influence circuitry over a distance, was "as powerful as Orac" (according to Kerr Avon) but had the capacity to enslave all of humanity. Restraining circuits were needed and built, but the android killed Muller before they were fitted, ripping off its creator's head to pose as Muller. By some means unspecified, the android was able to effect facial movement and speech in the head.
A woman named Vena came to Xenon some time before Muller: Avon described her relationship with Muller as "recreational". She may have been Muller's wife, though this was never explicitly stated - Tarrant referred to her as "Muller's lady".