Loki Laufeyson

"You were always a talented liar, brother, always have been."

- Thor

Loki is the god of mischief in Norse mythology and an antihero as well as a supervillain in the Marvel Cinematic Universe. He is adopted brother of Thor, the adopted son of Odin and Frigga and the biological son of Laufey and the enemy of The Avengers. He is also the main antagonist in the 2012 film adaption.

Thor
Adopted by Odin and Frigga at the end of the Asgardians' war with the jotuns, Loki was treated as a prince of Asgard and never informed of his true heritage throughout his youth. Loki is smaller, thinner, and darker in eyes and hair while paler in complexion than the Asgardians and is treated with less respect and acceptance because of it. Throughout their childhood it is implied that Loki spent much of his time trying to prove himself as Thor's equal while being ridiculed for his obvious inadequacies which led to him studying sorcery and magic instead of trying to acquire strength that he would never attain. Jealous of his of step-brother Thor, Loki allowed several Jotuns to enter Asgard to try and steal the Casket of Ancient Winters during Thor's coronation as a means of trying to interrupt his brother's special moment. In the wake of this intrusion, Thor opted to launch a counterattack on Jotunheim with a number of his friends, and while Loki initially tried to dissuade his brother, he eventually relented and went along with the plan.

Once in Jotunheim, Thor again led them into conflict and attacked the Jotuns even after being granted safe passage home. During the ensuing fight, Loki uses his abilities to create false versions of himself to kill a Jotun warrior and is then attacked by another that siezes him by the wrist. Loki is surprised by his own resistance to the Jotuns' freezing touch, a revelation that led him to conclude that he was at least partly Jotun rather than an Asgardian as he had been led to believe.

Loki confronted Odin over his lineage, and learns that Odin discovered him as an infant left to die in the temple of the Jotuns during the battle. Odin does not reveal that Laufey had hoped to do away with his misshapen son, but does reveal that his purpose in rescuing him was not solely out of compassion, but also in the hopes that peace could be brought permanently through Loki (he also asserts that those plans no longer matter because of Thor's actions). Infuriated that he had been lied to and had been taunted with the promise of a possible birthright, Loki shouts hatefully at Odin and, overwhelmed by the stresses of both his sons and angry wife coupled with the impending war with Jotunheim, Odin falls into the deep "Odinsleep" in front of him. With Thor already banished to Earth for the attack on Jotunheim, Loki is offered the position of king by his mother and assumes the role of Asgard's regent. From his position of power, he continued to manipulate others, firstly making Thor believe Odin had died, then forcing obedience from other Asgardians and finally manipulating the Jotuns into making an attempt on Odin's life.

When Thor's friends disobeyed Loki to bring word of his actions to Thor, Loki responded by sending The Destroyer after them to eliminate Thor. This action proved his undoing when Thor's courage in confronting the automaton paved the way for his return, and just as Loki revealed his double-cross against the Jotuns who were infiltrating Asgard, Thor arrived to challenge him over his actions. The resulting fight quickly moved to Heimdall's Observatory where Loki had opened a portal that would destroy Jotunheim. Thor's power ultimately overpowered Loki's cunning, at the cost of the observatory and the Bifrost.

As Loki fell into the abyss below, the spear in his hand was grabbed by Thor who in turn was anchored to the remnants of the bridge by the newly-awakened Odin. He appealed to his stepfather that by annihilating the Jotuns he was doing what was best for Asgard. Odin sadly rejected this, and with his Asgardian life now in tatters Loki released the spear and allowed the void to claim him.

The trickster was not so easily felled however, and found his way to Earth where he began to influence the human population again. One in particular, Erik Selvig, who was summoned by S.H.I.E.L.D. to turn his scientific knowledge to the task of unlocking the secrets of a mysterious cube also known as Odin's Tesseract. Loki, as an apparition in control of the man, whispered words of encouragement to proceed.

The Avengers
After his bid to overthrow the throne of Asgard was thwarted by his brother Thor, the evil Loki retreated to lands unknown to plot his revenge. Not just against his brother, but against Earth, whose inhabitants Thor now protects. Loki, now returns with a nefarious plot to conquer Earth and will stop at nothing to see his vision realized. When his misuse of power threatens the entire planet, it may take more than The Avengers to stop him.

Character traits
Unlike his stepbrother, Loki is not an impulsive man, quite the opposite: thoughtful, manipulating, farseeing, he's the perfect tactician. Loki is mischievous by nature, always eager to prove himself: being physically weak, he developed a sharp intellect and an acute mind to overcome his handicap amond the Asgardians warriors. He's pitiless and obstinate, ready to destroy everything on the path to his aims. Brilliant and smart, he's an incredible foe for a society mostly based on mindless combatants.

Being a misshapen Frost Giant, Loki possesses some of the characteristics of his kind, as the resistance to extreme cold and to his brethrens's frost powers. He also possesses superhuman physical abilities, such as strength, stamina, speed and reflexes, but to an extend equal or even near to the Asgardians. He's a skilled magician, specialized in the art of illusion, and can create mirages and false images of himself, make himself invisible to anyone, included the omniscient Heimdall, and can even control the minds of lesser beings like humans. Loki proves some skills in combat wielding Odin's spear, Gungnir.

Powers

 * Superhuman Strength: Loki possesses a formidable strength as a result of his jotun lineage, that is comparable to his Asgardian contemporaries.
 * Superhuman Durability: As a Jotun, Loki has a resilient body with a tolerance for trauma well above what a human body can endure. Of particular note is his pronounced tolerance for cold.
 * Superhuman Longevity: Loki has the capacity to live for hundreds, perhaps thousands, of years.
 * Sorcery: Loki is a master of magic. He can create illusions, including copies of himself and can influence people with his mind. During the battle in Jotunheim, he can use or throw piercing energy daggers to injure them. He can conceal himself or others from sight. In the movie, Loki masks the Frost Giants from Heimdall. Loki can summons objects out of thin air. In the movie, He summons The Casket of Ancient Winters and used it against Heimdall freezing him solid.
 * Teleport: Loki can travel to other dimensions without the Bifrost. He can even teleport others. The full limits of this ability aren't known.

Weapons

 * Loki uses magic artifacts like Odin's spear, Gungnir, which can project mystical blasts of energy, or the Casket of Ancient Winters.

Friends and Allies

 * The Destroyer
 * Warriors Three (before the incident with Thor's banishment)
 * Sif (also befre the incident with Thor's banishment)
 * Erik Selvig - Unwitting Pawn

Enemies

 * Odin - Adopted Father
 * Frigga - Adopted Mother
 * Thor - Step-brother
 * Laufey - Biological Father (It should be noted that Laufey wanted to kill Loki at birth and left him to die, he ordered him to be executed during his visit to Jotunheim to offer an alliance, and likely would have killed him after destroying Odin; Laufey hated Loki for his small appearance and weakness.)
 * The Avengers (including Iron Man, The Incredible Hulk, Hawkeye, Captain America, Thor, and SHIELD agents)
 * Frost Giants
 * Heimdall (Loki attacks him after discovering the betrayal of the Warriors Three and Sif)
 * Humans that oppose him

Behind the scenes

 * At first, Tom Hiddleston auditioned to play Thor, but Kenneth Branagh decided he was fitter to play Loki.
 * Hiddleston had to go through a strict diet since Branagh wanted Loki "to have a lean and hungry look".
 * Hiddleston took inspiration from Peter O'Toole's interpretations from The Lion in Winter and Lawrence of Arabia.

Appearances/Actors

 * Canon (2 films)
 * Thor (First appearance) - Ted Allpress, Tom Hiddleston
 * The Avengers - Tom Hiddleston

Trivia

 * Loki is based on the god of mischief in Norse mythology.
 * In the comics, Loki never meets his biological father after being adopted by Odin, while in the movie he even allies (and betrays) him.
 * At the end of Thor, Loki looking at the Cosmic Cube and deceiving Nick Fury is a hint to the comics continuity, in which he's the villain to stop which The Avengers assembled for the first time.
 * Loki was the main antagonist in Thor, and will also be an antagonist in The Avengers.