Representative of the Andari Federation on the planet Langara's Joint Ruling Council. Tarthus traveled to Earth with representatives from neighboring nations Kelowna and Terrania to begin negotiations for the resettlement of their people, only to discover that it was the Kelownan naquadria bomb that initiated the process that could destroy their entire world.
Tarthus was extremely difficult to deal with and found it impossible to negotiate with the other two parties. When Jack O'Neill arrived to explain that their short-sightedness had brought an end to resettlement negotiations, Tarthus and the others began to reassess their position. But eventually the excavation deep into Langara's crust was successful in averting the planetary disaster.
Fallout - Tarthus travels to Earth to commence negotiations for possible alternatives in the event the excavator fails.