 They become enemies of the Atlantis Expedition in the first season and once try to invade Atlantis, though after a coup d'état in the second season they have been more favorable towards the city.The main adversaries on "Stargate Atlantis", the Wraith are the dominant species in the Pegasus galaxy.They are biologically immortal hive-based humanoids who feed on the "life-force" of humans, causing them to "lose years" in a way similar to aging.