An introduction to the heroes, allies and villains of 'The Avengers'

Like Thor, Loki (Tom Hiddleston) is a demigod from Asgard. However, he is only Thor's adoptive brother; Loki's real father is Laufey, king of the Frost Giants. This fact leads to the rift between Thor and Loki detailed in the 2011 film "Thor." Loki ends up on Earth, seeking revenge on his brother and the people who aided him. While physically weaker than Thor and unable to wield Mjolnir, Loki has many magical powers, including illusion, shapeshifting, and mind control.

Appearances in other Marvel films: Loki was the main adversary in 2011's "Thor."