List of Recurring Alien Characters in Stargate SG-1 - Asgard

The Asgard are a benevolent race that, according to the mythology of Stargate, gave rise to Norse mythology on Earth and inspired accounts of the Roswell grey aliens. The Asgard can no longer reproduce and perpetuate themselves by transferring their minds into new clone bodies as necessary. Extremely advanced technologically, the threat of their intervention shields many planets in the Milky Way from Goa'uld attack, including Earth. They also provide much assistance to Earth in the way of technology, equipment, and expertise. Their main adversary in Stargate SG-1 are the mechanical Replicators, against which they enlist the aid of SG-1 on several occasions. The entire Asgard civilization chooses to self-destruct in "Unending" due to the degenerative effects of repeated cloning. A small colony of Asgard still exist in the Pegasus galaxy that were able to stop cloning diminishing returns. Stargate SG-1 had several Asgard puppets, and six puppeteers are necessary to make the different parts of the main Asgard puppet work. On set, Teryl Rothery (Dr. Frasier) wearing CGI reference gear was the "stand-in" for Thor ("Small Victories" episode 4.1) and Heimdall ("Revelations" episode 5.22) when full motion is required and puppets could not be used.

• Freyr, voiced by Brian Jensen (season 5) – A member of the Asgard High Council, named after Freyr, the Norse fertility god and god of love. SG-1 first encounters Freyr as a Viking hologram on the Asgard-protected planet K'Tau in season 5's "Red Sky", but Freyr refuses to help SG-1 to avoid a violation of the Protected Planets Treaty. SG-1 meets Freyr and the Asgard High Council again in "Fail Safe" to save Earth from an approaching asteroid, and again receive no help. Freyr eventually requests SG-1 to rescue one of their scientists in "Revelations" and protects SG-1, the Asgard scientist Heimdall and his studies with a fleet of three O'Neill class battleships.
• Kvasir, voiced by Trevor Devall and Morris Chapdelaine (seasons 9–10) – An Asgard scientist and expert in time-dilation technology. He is named after Kvasir, a Norse god and wisest of the Vanir. As Thor is busy in the Asgard home galaxy in season 9's "Ripple Effect", Kvasir visits Earth in Thor's stead to help Earth fix a problem with alternate realities. Kvasir also assists SG-1 in battling the Ori in season 9's "Camelot" and helps to repair the transporters of the Odyssey in season 10's "Flesh and Blood".
• Thor, voiced by Michael Shanks (seasons 1–8, 10) – The Supreme Commander of the Asgard Fleet. SG-1 first encounters Thor as a humanoid Viking holographic recording on the planet Cimmeria in season 1's "Thor's Hammer", and as his true self in season 2's "Thor's Chariot" as he saves Cimmeria from Heru-ur's invasion. Thor remains a recurring character and appears in all following seasons except season 9, risking his life multiple times to save SG-1 and Earth from both the Goa'uld and the Replicators, while SG-1 save him on many occasions from the Replicators and once from Anubis (in season 5's "Revelations"). Thor makes his last appearance in the series finale, "Unending", leaving SG-1 the entire knowledge of the Asgard race after his race's attempts to solve their genetic difficulties have failed.
• Hermiod was the Asgard overseer present on the Deadalus during early seasons of Stargate Atlantis