His father, Zephon, was impersonated by the First Doctor, who used the disguise to steal the Taranium core of the Time Destructor. Due to this, Zephon was then exterminated for his failure. Later on, the Doctor used the Time Destructor which caused the destruction of Kembel. (TV: The Daleks' Master Plan)
Celation later informed Zephon's family about the events on Kembel. This caused the family to be hated among the people of Zephon and of the Syndicate[statement unclear] who did not allow the young Zephon to join the newly made Syndicate, causing him to further hate the Doctor. (AUDIO: Time's Assassin)
The young Zephon went to the destroyed Kembel and created a force field around a newly created jungle enclosure with a building for unwanted relatives of well-known families to go to prove his worth to the Syndicate. After the Fourth Doctor arrived, Zephon tried to kill him, (AUDIO: The False Guardian) only to be stopped so the Doctor could be experimented on.
After informing the Syndicate of the Doctor's capture, the Syndicate demanded that the Doctor be brought to them alive, and in return would give Zephon the encrypted coordinates and membership for the Syndicate. The experiment caused the Doctor to become a part of the WaveFront, so Zephon failed to become a member of the Syndicate. (AUDIO: Time's Assassin)
Soon after, the Varga plants, from the jungle, invaded the building, causing Zephon to panic and try to escape in his ship, only to be found by Ann Kelso who interrogated him about the Syndicate location. After revealing that he knew nothing, he tried to kill Ann. Ann was able to kill him (temporarily regressing to her true personality of Space Security Service agent Anya Kingdom) and later blew up his ship to obscure her part in his death. (AUDIO: Time's Assassin)