Loki Laufeyson, later known through adoption as Loki Odinson, is a character portrayed by Tom Hiddleston in the Marvel Cinematic Universe (MCU) media franchise, based on the Marvel Comics character and Norse mythological deity of the same name. He is depicted as the God of Mischief and initially nemesis to his adopted brother, Thor.

Raised as a master of Asgardian magic and sorcery, Loki plots to take the Asgardian throne from Thor. After that fails, he attempts to conquer Earth, inadvertently driving the formation of the Avengers, but is imprisoned in Asgard. He briefly replaces his adoptive father, Odin, as Asgard's ruler, then turns antihero and helps his brother save the planet from their sister Hela, before being killed by Thanos. An alternate version of Loki from 2012 is recruited by the Time Variance Authority (TVA) and encounters other versions of himself, including a female version named Sylvie, with whom he falls in love. They work together with TVA members Mobius, Hunter B-15 and Ouroboros to stop He Who Remains. The alternate version of Loki later sacrifices himself to watch over and maintain the multiverse.