A member of the Organian council who can sense events at a distance and shares Ayelborne's calm refusal to take sides.
Trefayne serves on the council of elders on Organia alongside Ayelborne. In Errand of Mercy he is able to perceive faraway events, informing Kirk and Spock of the Klingon fleet's arrival and of the occupiers' actions, which puzzles the visitors given the planet's apparent lack of technology.
Like the other Organians, Trefayne refuses to take part in the conflict between the Federation and the Klingons. When the Organians reveal their true nature as beings of energy, his foresight is explained. He was played by David Hillary Hughes.