|Out of universe information|
Alexi Vaselov was a Colonel in the Russian Air Force who was brought to Stargate Command in hopes of becoming the first Russian member of SG-1. He had a sister in Russia whom he had included in his will. Before coming to the SGC, he went to visit his friend Anatole Konstantinov, who was host to Anubis. Anubis left Konstantinov and entered Vaselov.
Once at the SGC, Anubis tried to get Brigadier General Jack O'Neill to allow him to go through the Stargate. When Anubis failed, he left Vaselov and entered Dr. Daniel Jackson. Unfortunately, the damage to Vaselov's system was already done. Vaselov was killed when he forced Anubis (who was possessing O'Neill at the time) to possess his body instead because he was already dying. In doing so, he saved O'Neill and sacrificed himself. Anubis then left Earth through the Stargate, unaware it had been dialed out to an uninhabited planet, too cold for Alexi to survive on, ultimately resulting in Alexi's own death. He therefore left Anubis with no body to repossess. However, Anubis escaped that world, though it is unknown how he managed to do so. (SG1: "Lockdown", "Reckoning, Part 1")