Thor is the Supreme Commander of the Asgard Fleet and a member of the Asgard High Council. He brought the Cimmerians from Earth, known as Midgard, and protected them from the Etins, or Goa'uld, by taking on the persona and holographic representation of the imposing Norse god. According to Norse mythology, Thor was a powerful warrior and friend to humans, who ruled from Thrudvang, his home in the stars, and whose weapon, Thor's Hammer, produced lightning and thunder.
Like all Asgard, Thor resembles a Roswell Gray, and he revealed himself in his true Asgard form after SG-1 proved themselves worthy in the Hall of Thor's Might. From his mothership, the Biliskner, he defeated the forces of Heru'ur on Cimmeria. As a friend to Earth, he acted as an intermediary to negotiate with the Goa'uld System Lords to include Earth in the Protected Planets Treaty.
When his ship was overrun by Replicators, Thor turned to SG-1 for help in halting their spread. He was kept alive in a stasis pod and rescued by SG-1 as the Biliskner was destroyed, and he returned to Earth to engage Carter's assistance in defeating the Replicators in his own galaxy.
Thor was captured by Osiris and Anubis, who used a mind probe to access the knowledge of the Asgard in his brain. Although his body was rescued by SG-1, his mind had been downloaded into the computer core of Anubis's ship, and his consciousness remained intact within the ship's memory crystals until SG-1 retrieved the crystals from the abandoned ship, and his consciousness was transferred into a new cloned body.
Faced once again with the Replicator threat, Thor returned to seek SG-1's help to use the inferior technology of the Prometheus to repair a time dilation device that would trap the Replicators in a time dilation bubble on Hala. In gratitude for the efforts of SG-1 on behalf of the Asgard, Thor appeared on Earth before a meeting of international ambassadors to state the preference of the Asgard High Council that the SGC remain under the command of Hammond and his SG teams. As an ally and true friend of Earth, Thor has even met with the President, and he has shared Asgard technology including shields, weapons, beam technology, and a hyperdrive for use on the Prometheus.
Thor returned again at the request of SG-1 and intervened to halt Loki's unsanctioned experiments on humans, and he repaired the cloned DNA of Young Jack O'Neill to allow him to live a normal life. When O'Neill was placed in stasis after receiving the knowledge of the Ancients from the repository on P3X-439, Thor was able to restore him, and he used the Ancient knowledge in O'Neill's mind to synthesize a disruptor weapon that successfully defeated the Replicators on Orilla. Thor also assisted SG-1 by removing evidence collected by Alec Colson and by creating a holographic projection on live television in order to discredit Colson's claims of the existence of alien life and to protect the secrecy of the SGC.
When the Replicators entered the Milky Way galaxy, Thor shared a disruptor satellite to defend the Alpha Site against invasion, and when the Replicators learned to make themselves immune to the technology, Thor cooperated with Carter to modify the disruptor to overcome the immunity. Their modifications were successful, but the Replicators quickly adapted, and Thor departed across the galaxy when his ship was boarded. He survived the invasion, however, and after the elimination of the Replicators from the galaxy he sent his congratulations to the SGC with a promise to drop by for a visit once his consciousness had been downloaded into another new cloned body.
When Thor next contacted Earth, it was to invite the Odyssey to Orilla and to deliver the devastating news that the Asgard race was dying. He had come to see the humans of Earth as the Fifth Race, and he intended that the Asgard knowledge should be passed on. Thor beamed aboard to supervise the installation of all the Asgard knowledge and most current technology aboard the Odyssey in what would be the final legacy of the Asgard. As the installation of the upgrades was completed, however, three Ori warships appeared above Orilla, and the Asgard made the deliberate decision to end their civilization. In a massive planetary explosion, Orilla disintegrated, and Thor and the Asgard were gone.
Voice of Thor: Michael Shanks
Holograph of Thor: Mark Gibbon
Cross Reference: Adara System, Aegir, Anubis, Asgard, Asgard High Council, Biliskner, Cimmeria, Cimmerians, Crystals, Disruptor, Freyr, Gairwyn, Hala, Hall of Mjollnir, Hall of Thor's Might, Heimdall, Heru'ur, The Daniel Jackson, Kendra, Loki, Mind Probe, The O'Neill, Orilla, Osiris, Penegal, Prometheus, Protected Planets Treaty, Replicators, Stasis, Thor's Hammer, Time Dilation Device
Episode Reference: Thor's Hammer, Thor's Chariot, Fair Game, Nemesis, Small Victories, Revelations, Descent, Prometheus, Unnatural Selection, Disclosure, Fragile Balance, New Order, Covenant, Gemini, Reckoning, Unending