I am Loki of Asgard, and I am burdened with glorious purpose.
~ Loki introducing himself to Nick Fury.
Kneel before me. I said… KNEEL! Is not this simpler? Is this not your natural state? It’s the unspoken truth of humanity that you crave subjugation. The bright lure of freedom diminishes your life’s joy in a mad scramble for power. For identity. You were made to be ruled. In the end, you will always kneel.
~ Loki to a crowd of humans.
Loki Laufeyson is a major character in the Marvel Cinematic Universe. He started off as the main antagonist of both Thor and The Avengers, but later becomes the anti-heroic tritagonist of Thor: The Dark World, the deuteragonist of Thor: Ragnarok, and a minor character in Avengers: Infinity War.
He was portrayed by Tom Hiddleston, who also portrayed Thomas Sharpe in Crimson Peak, and voiced Captain James Hook in The Pirate Fairy and later Lord Nooth in Early Man.
Loki is the God of Mischief, and an expert liar. Though Loki tries to take over Asgard and Earth, all he really wants is the approval of his father and brother. He is a smart and intelligent man, and he will stop at nothing to fulfill his quest. He is usually considered a lying and manipulative trickster, but this is only because he wanted to be an equal to Thor. Therefore, Loki does have emotion, and he does communicate with some people, despite his power and arrogance.
His personality develops with each film he appears in: In Thor, he is initially good and altruistic. However, as soon as he discovers that Odin lied to him about being his son and that he was actually a Frost Giant, which everyone on Asgard told him were vicious and heartless monsters. Loki broke down as he started to feel like Odin saw him as a monster as well, which caused him to believe it was the reason why he would never give him the throne and ignored him over Thor his whole life. Because of this, Loki snapped and attempted to commit genocide on his own people to prove his loyalty. He showed a darker personality after those events and a lot of arrogance and vanity, as well as having no problem with manipulating people to get what he wants. Despite all of this, Loki was still shown to deeply love his adoptive mother Frigga, and shows a sense of remorse for his actions in the end of the movie, telling Odin that he could have done better. But, after Odin denies him, Loki attempts suicide, believing there was no hope of redemption.
In The Avengers, Loki's sanity had slipped away due to being threatened and tortured by Thanos. He is sweating, twitching and appearing to be suffering from heat exhaustion--which would, of course, be the perfect way to torture a frost giant. He may be trying to play both sides against the middle, appearing to attempt a takeover but doing it in the most inept way possible.
In Thor: The Dark World, Loki was shown to throw sarcastic comments at Odin who judged him for his actions. However, his sarcasm dropped as soon as he was told that he wasn't allowed to see his mother Frigga anymore, seeming as if he was trying his hardest to hold in tears. This got worse after he finds out that she was killed, causing him to feel extremly depressed and possibly shameful that the last interaction he had with her was an argument. However, he later joins Thor to avenge Frigga, and later sacrificed himself to save Thor. Although everyone believed Loki had died, it was soon revealed that he faked his death to get the throne.
In Thor: Ragnarok, Loki helps Thor on his adventures and had shown to care about his well being several times. However, he did still have some trouble remaining on his side. Because of this, Thor couldn't trust him and left him behind. Despite Thor's actions, Loki still shows up to rescue Thor later, showing that he truly wanted to atone for his mistakes. In the end, Loki also retained the brotherly bond with Thor and seemed to finally accept Thor being king.
In Avengers: Infinity War, during Thanos's attack on the Asgardian ship, all the survivors, save for Thor and Hulk, are killed, including Heimdall. Thanos then orders Ebony Maw to torture Thor to death, in order to force Loki to give him the Tesseract. Despite initially claiming not to care about his adopted brother, Loki eventually relents and gives Thanos the space stone. Loki then claims that he wishes to defect to Thanos's side. Although Thanos recalled Loki's previous attempt to unsuccessfully conquer Earth via invasion, he apparently reconsiders when Loki - kneeling before Thanos - swears his "undying loyalty" to the Mad Titan. In that moment, Loki lunges for Thanos with a summoned dagger. Thanos, easily blocking the attack, coldly rebukes Loki for his poor choice of words earlier, before strangling the trickster god. With his final breath, Loki tells Thanos that he will never be a god. This shows that Loki had finally achieved redemption and he had truly accepted his parentage while still considering himself an Asgardian.
Powers and Abilities
Loki's main weapon may be his intelligence, but he is still an extremely powerful being:
Superhuman Physical Attributes: Loki was strong enough to knock Thor and Captain America to the ground in combat, throw Stark across a room and through a window, and send other humans flying with a single strike. He is shown as being only phased after taking strikes from Captain America's shield, fists and kicks, was also unharmed by machine gun bullets, an explosion from one of Hawkeye's arrows and rather long falls. Loki is capable of moving at speeds and evading attacks beyond human capabilities which he used in his battle with Captain America. His Jotun metabolism also has a regenerative healing factor. He recovered from being struck by Iron Man's repulsors and Thor's strikes and survived a beating from the Hulk that would have killed most others.
Cryokinesis: Not long after learning of his Jotun blood, Loki discovered and mastered an ability to create and manipulate ice, which he used to freeze the Bifrost in place when trying to destroy Jotunheim.
Mystical Prowess: Using his inborn skills and his teachings by Frigga, Loki is capable of using impressive magical abilities for a wide variety of situations. He can create realistic physical illusions. He can use this to give himself a vast advantage over his enemies, taking trickery and deception to an advanced level. He can conjure up weapons such as his blades. He can even conjure up Relics of Great Power, such as the Casket of Ancient Winters or the Tesseract.
Genius-Level Intellect: Centuries of learning and training have enhanced his mental faculties as well as his intellect. Despite being new to Earth, he quickly adapted to their lifestyle and the use of Earthly technology.
Master Martial Artist: Centuries of training in Asgard has made Loki an extremely dangerous and unpredictable opponent. He was able to kill several Frost Giants, match Thor, overpower Captain America and kill a group of Dark Elves in combat. He is completely capable of fighting with spears, knives or even his bare hands, with utter ease.
Weapons Handling: Loki's signature weapon is a dagger which he handles with marvelous skill, using it to defeat several Frost Giants and Dark Elves single-handedly. He is proficient with throwing knives which he used to kill SHIELD agents with a perfect on the mark throw. He is also formidable with spears, using Gungnir and the Chitauri spear to great effect as close combat weapons, rifles and tools.
Frost Giants - Biological Family
Laufey † - Biological Father and Victim
Bor † - Adoptive Grandfather
Odin † - Adoptive Father and former king
Frigga † - Adoptive Mother and former queen
Thor - Adoptive Brother and Situational Ally
Hela † - Adoptive Sister, Enemy and Attempted Killer
Enough! You are all of you beneath me! I am a god, you dull creature, and I will not be bullied by-
~ Loki's short last words to Hulk before being beaten by him.
Oh, dear. Is she dead?
~ Loki, just after Jane collapses.
I am Loki of Jotunheim, and I have brought you a gift! I ask only one thing in return; A good seat from which to watch Asgard burn.
~ Loki to Malekith while carrying out the plan he created with his "brother".
You must be truly desperate to come to me for help.
~ Loki to Thor as he requests his aid in defeating Malekith.
Well done, you just decapitated your grandfather!
~ Loki to Thor.
An ant has no quarrel with a boot.
~ Loki to Nick Fury.
Are you ever not going to fall for that?
~ Loki to Thor in "The Avengers" after he uses his duplication ability to trick him.
Brother, whatever you're doing, I suggest you do it faster.
~ Loki to Thor.
Odin continues to bring me new friends. How thoughtful!
I have to get off this planet!
~ Loki upon the reveal of Hulk being Grandmaster's champion.
We have a Hulk!
~ Loki to Thanos.
You will never be a god.
~ Loki's last and final words before his death.
Loki is the first villain to appear in more than one film of the Marvel Cinematic Universe - possible exceptions include Thanos (Appearing in end-credits scenes in The Avengers and Avengers: Age of Ultron, and debuting properly in Guardians of the Galaxy and Avengers: Infinity War), Baron von Strucker (Who appeared in a mid-credits scene in Captain America: the Winter Soldier and as an antagonist in Age of Ultron), and Klaw (Who appeared in both Age of Ultron and Black Panther). He has appeared in Thor, The Avengers, Thor: The Dark World, Thor: Ragnarok and Avengers: Infinity War making him so far the most recurring independent villain of the series.
He is the first antagonist in the Marvel Cinematic Universe to serve as the main antagonist of more than one film.
Loki is the second antagonist to be defeated by a lone main protagonist so far in the MCU. Iron Monger and Aldrich Killian were both killed by Pepper Potts; Malekith was crushed by his ship; Red Skull was vanished due to the Tesseract; and Whiplash was defeated by Iron Man with the help of War Machine. Loki and Thor's fight in Thor ended in a stalemate whereas in The Avengers, Loki was beaten by Hulk. Ironically, Hulk also beaten by Abomination, making Hulk the victor in two consecutive good vs bad fights and the first one to beat an antagonist in a fair fight without any assistance, the second being Ant-Man who defeated Yellowjacket.
Loki was Tom Hiddelston's breakout role.
The scene in Marvel's The Avengers in which Loki is overpowered by the Hulk is considered to be one of the funniest and most memorable moments in the MCU.
Hilariously, in MCU series itself, the said beating at hands of Hulk resulted Loki to develop genuine fear towards him as upon Hulk being revealed to be Grandmaster's champion, he visibly terrified that he rather leave Saakar than meeting him again.
Loki is one of the four main villains of the MCU to actually succeed in his plans, as he managed to take control of Asgard for himself in Thor: The Dark World. The other three are Helmut Zemo (who has managed to split the Avengers apart in revenge for his family's demise in Captain America: Civil War), Ghost (who has managed to obtain quantum energy to cure herself from a fatal disease in Ant-Man and the Wasp), and Thanos (who has managed to collect the Infinity Stones to wipe out half of the universe's populace in Avengers: Infinity War).
Because of the reason he appears in more than one film, overall, he is considered to be the secondary antagonist of the entire MCU, but after his redemption he is considered one of the main protagonists of the MCU.