Dammar was a Nyrian male who led an attempt to commandeer the USS Voyager in 2373. As such, he was the first of his people to use the translocator to arrive on Voyager. He claimed to be from a colony on Nyria III, though his description of the Nyrian system did not match any star system in Voyager's records.
Once the entire Voyager crew was displaced to the Nyrian biosphere vessel, Dammar took command and oversaw efforts to restore its systems. Soon after, Taleen informed him that the Voyager crew had broken out of their habitat, prompting him to take Voyager to the biosphere vessel.
Using the translocator, Captain Kathryn Janeway had Dammar transported into the Argala habitat. As his species could not withstand the frigid temperatures there, Dammar surrendered Voyager and agreed to release all the prisoners on the biosphere ship. (VOY: "Displaced")