Zephon had gained the title after overthrowing the Embodiment of Gris in 3932. (AUDIO: Neverland) As a member of the Galactic Council, he represented his home galaxy at the seventh Council meeting (replacing Beaus). He allied himself with the Daleks in their plan to conquer the Solar System.
Zephon had persuaded Beaus and Celation to join as well. Although a powerful figure, some of his subjects, such as the Embodiment Gris and the planet Fisar, had contested his rule. Arrogant and self-important, he made the Council wait for his presence at the seventh meeting. This allowed SSS agent Bret Vyon to knock him unconscious and tie him up so that the First Doctor could impersonate him in the meeting.
The Doctor used the ruse to steal the Time Destructor's taranium core. Blamed by the Daleks for this set-back, Zephon announced he was leaving the alliance with Celation and Beaus, but they remained loyal to the Daleks, who then exterminated him for his failure. (TV: The Daleks' Master Plan)
Physically, Zephon resembled a humanoid with seaweed-like, tendriled hands. A cowl usually concealed his face, but his cloak was stolen by the Doctor, revealing a similarly-tendriled head without distinguishable features.