Tremas of Traken was one of the five Consuls of Traken to the Keeper of Traken of the Traken Union and at one time a candidate for Keeper.
Tremas married his second wife Kassia, who was also a consul. He already had one daughter, Nyssa, at that time. (TV: The Keeper of Traken) His father died before Nyssa was born. (AUDIO: The Toy)
However, Kassia came under the influence of the Melkur and she turned against the Traken Union. When Tremas was considered unfit to become Keeper for helping the Fourth Doctor and Adric, Kassia was chosen. When she became connected to the Source, the power of the Keepers, she was destroyed and replaced by the Melkur, who it was revealed was really the Decayed Master. Tremas helped the Doctor stop the Master and still save the Source.
Shortly after the Doctor and Adric left Traken, Tremas noticed a grandfather clock. As he went to investigate it, he became immobilised on touching it and the Master emerged. With some of the Keeper's powers still lingering, the Master assimilated Tremas's body. As it became younger in appearance, the Tremas Master gleefully chuckled over his new body, and left Traken. (TV: The Keeper of Traken)
Tremas's fate greatly troubled his daughter Nyssa. Due to the Trakenite belief in the connection between the soul and the body, she believed that Tremas could never be at peace while the Master was using his form. (PROSE: Empire of Death)
Posthumously, Tremas had two grandchildren, Neeka and Adric Traken. (AUDIO: Winter, Prisoners of Fate) Later in life, Nyssa used her father's name as her personal password. (AUDIO: Heroes of Sontar)
The Garden of the Dead almost recreated Tremas from Nyssa's memories, but instead a replica of the Master in Tremas's body was created. (AUDIO: Gardens of the Dead)
