Who he is: Loki Odinson, a.k.a. Loki Laufeyson, a.k.a. God Of Mischief
His power: Loki possesses the superhuman strength, speed, agility, and stamina of a Frost Giant as well as a healing power. He was also taught Asgardian sorcery, of which his most deft power is that of disguise and doubling—appearing in the guise of another person or projecting a second, incorporeal image of himself.
His story: As recounted in Thor, Loki is the son of Frost Giants, but was rescued as an infant and brought to Asgard by King Odin, where magic allowed him to look and be raised as one of Odin’s own sons alongside Thor. However, his hunger for power leads him to cut a deal with the Frost Giants, sneaking them into the castle in an attempt to steal an ancient Frost Giant weapon. After they’re defeated, Loki’s manipulations get Thor exiled to Earth and stripped of his power. Odin’s illness then allows Loki to ascend the throne, though he kills Laufey, King Of The Frost Giants, as part of a plan to prove his worth. Instead, he’s overpowered by Thor and flies off into space following the destruction of the rainbow bridge.
He next shows up in The Avengers, having been granted the power of a scepter containing one of the infinity stones and control of an alien race, the Chitauri, whom he leads in an invasion of New York City. He is defeated by the Avengers, and his army is rebuffed. Sent back to Asgard, he resides in prison, until the arrival of Malekith and the Dark Elves leads to the death of Frigga, Loki’s adopted mother. Enraged, he agrees to join Thor and get revenge on Malekith. However, after freeing Jane Foster of the Aether possessing her, Loki is seemingly killed by the Dark Elves. At the end of Thor: The Dark World, it’s revealed Loki has returned to Asgard and is sitting on the throne, impersonating Odin.
Played by: Tom Hiddleston
Currently, Loki is: Ruling Asgard in disguise.
Where will we see him next? Thor: Ragnarok, due out November 2017.