With the Chancellor Torbis, he convinced the young King Peladon to take the throne when his father died.
Hepesh believed that Peladon would be exploited by Galactic Federation if they were to join it, and conspired with Arcturus against the throne. He went so far as to use Aggedor, the Royal Beast of Peladon, to kill Torbis. When Hepesh tried to order Aggedor to kill the Third Doctor, the Beast turned on him instead, inflicting a fatal wound. Hepesh died in the King's arms. (DW: The Curse of Peladon)