Kalfas was a Commander of the Tagrean Security Forces. He was frequently in opposition with Ashwan, the Tagrean head of state, particularly on matters of defense. Kalfas continually believed Ashwan was too "soft," and throughout his political career, Kalfas was winning more public opinion.
When the Prometheus entered Tagrean orbit, Kalfas was quick to judge them as a threat after an explosion occurred in their air space (the detonation of its hyperdrive engine), sending rockets up to destroy the ship. Ashwan stopped the attack and permitted the ship to enter the atmosphere.
Kalfas wished the alien presence wiped clean from Tagrea, eager to forget the past thousands of years that had been erased from their history. He was opposed to searching for the Stargate, believing that the doorway would bring greater numbers of enemies. When the Stargate began to emerge from Tagrean soil Kalfas organized a military coup to go in and capture Jonas Quinn, Teal'c and the Tagreans they had managed to bring to their aid. Ashwan arrived aboard the Prometheus, ringing to the dig site and, after careful verbal persuasion, Kalfas' men backed down. Eventually he was taken into custody. (SG1: "Memento")