fundamental difference in plot structure and set design from other series. There is a disjunction between politics on Earth and the realities of fighting an interstellar war. The Stargate also helps to speed up the exposition of the setting. Ancients The race of the Ancients is first mentioned in the Stargate SG-1 season 2 episode "The Fifth Race" as the original builders of the Stargate network and members of the former Alliance of four great races. They were considered humanity's predecessors, originally establishing Earth as their homeworld after they migrated to the Milky Way, and having seeded multiple galaxies to allow life to evolve on uninhabited worlds. At the time that the Stargate franchise takes place, the Ancients have long since "ascended", i.e. they shed their physical bodies and live eternally as pure energy on a higher plane of existence with an increased power and capacity for learning. While they are no longer physically present in the universe, their highly advanced technology—including the Stargate—remains behind, all of which has shown to be almost entirely resilient to the decay of time, and has also proven to be the most advanced technology anyone has ever encountered. With humans from Earth as their closest descendants both from a genetic standpoint and an evolutionary standpoint, they have shown the most proclivity in utilizing Ancient technology when they encounter it. For the first six seasons of Stargate SG-1, the ascended Ancients maintain a strict rule of noninterference in mortal affairs of the material galaxy, and the interactions between humans of Earth and the Ancients are restricted to the outcast Ancient characters Oma Desala and Orlin; the Ancients' ascension was also used as a plot device for the departure of actor Michael Shanks (Daniel Jackson) in season 6 of Stargate SG-1. The fictional background of the Ancients was extended with the franchise's Atlantis mythos that began in the Stargate SG-1 season 6 finale "Full Circle", and which also served as the basis for spin-off show Stargate Atlantis. The Ori arc of Stargate SG-1s seasons 9 and 10 expanded the Ancient mythos further. Asgard A benevolent race that, according to the mythology of Stargate, gave rise to Norse mythology on Earth and inspired accounts of the Roswell Greys. The Asgard can no longer reproduce and therefore perpetuate themselves by transferring their minds into new cloned bodies. Extremely advanced technologically, the threat of their intervention protects many planets