Remember, he had just been imprisoned at the end of the first Avengers movie. But when Loki died in Thor's timeline, the two had been through many struggles and reconciliations, finally becoming old friends and the brothers they were always meant to be.
Surtur is reborn and destroys Asgard, killing Hela. Aboard the Grandmaster's spaceship, the Statesman, Thor, now king, reconciles with Loki and decides to take his people to Earth.
While Loki is now more of a mischievous ally to Thor than an outright villain, their original villain/hero relationship was always so much more impactful than basically any other due to the fact that, throughout their entire childhood, they were good friends as well as siblings.
While Loki and Thor did, by heart, truly love each other as brothers, their intention to rule Asgard made them fierce rivals. However, Thor evolved himself by learning that a true leader doesn't start wars or seek to conquer other territories, while Loki sought to control the world and gain more power over others.
Some people utterly believe that Loki sacrificed himself for his brother's sake, and the truth is his actions and words alone were very telling: he loves Thor, he always has, and though both have had their disagreements and misadventures, they would without question die for each other in the end.
Loki is Thor's adopted brother and the Asgardian god of mischief. In his younger years, he and Loki were very close and good friends, even if occasionally irritated by Loki's mischief. However, it is later revealed that Loki was often jealous of Thor even back then, and resented being left in his "shadow".
Loki often hid a degree of jealousy that Thor was to become King, and felt that Odin perhaps favoured Thor over him. As Thor was always the center of attention, Loki found himself longing for a spotlight over the years, which manifested itself in extreme attention-seeking behaviour.
Most Marvel fans think that Odin favors Thor over Loki because the former is his natural son, while Loki is the adopted son of the giant Laufey. However, there is another, much deeper reason for Odin's favoritism, and it hides in the one-eyed god's past and his relationship with his brother Cul, the God of Fear.
Verity Willis was Loki's best and only friend for the longest time. Verity had the power to tell lies from truth, which Loki found interesting, seeing as he was the God of Mischief.
Loki says that Odin does a poor job in handing out honor in war to men, and that he's often given victory to the faint-hearted. Odin responds that even if this is true, Loki (in a story otherwise unattested) once spent eight winters beneath the earth as a woman milking cows, and during this time bore children.
Loki's season two finale marks the end of Tom Hiddleston's 14-year journey as Loki in the MCU, with uncertain prospects of returning until possibly Avengers: Secret Wars. Fans never got the long-awaited reunion between Loki and his brother Thor, but there's a small glimmer of hope.
Thor : Loki, I thought the world of you. I thought we were going to fight side-by-side forever, but at the end of the day you're you and I'm me and... oh, maybe there's still good in you but... let's be honest, our paths diverged a long time ago.
This caused Thor to send lightning towards them, toppling the mine on top of them. Loki apologized and confessed, saying he only thought of the challenge to get the Cup and gain as much respect as Thor. His brother forgave him and found a way out of the mine.
This fuels his unrelenting jealousy of Thor and feelings of inferiority. Despite his latent love for his family and occasionally helping Thor when he feels inspired, he typically betrays him.
He always hated Balder, and when Balder became virtually unkillable, he found a loophole and tricked Balder's own brother into killing him. And he and Heimdall never got along. They fought constantly over the years, and eventually, kill each other at Ragnarok. Does Loki really hate Thor?
In the films, his most prominent relationships are with his family, notably his adoptive brother Thor (see: Thorki) and his adoptive mother, Queen Frigga. In his TV series, Loki and a female version of himself called Sylvie fall in love (see: Sylki) and their relationship becomes a prominent point of the show.
Odin revealed that he wanted to gain a permanent peace between Asgard and Jotunheim by having Loki rule the world of the Frost Giants. Loki was disgusted by his own parentage and claimed that Odin could have never loved him the same way he loved Thor and would have never given him the throne.
Loki cast a spell on Odin, and left him on Earth. But this is not the reason he died. Odin made it clear that it was his time. In the MCU this is the start of Ragnarok.
Who would win in an MCU fight: Odin or Thanos? Without the Infinity Gauntlet, Thanos stands little chance against Prime Odin. Odin is stated to be able to shatter the Earth.
Summary. Loki's villain origins in the MCU stem from his discovery that he is actually the son of a Frost Giant, which led him to believe that Odin favored Thor over him, causing him to turn against his family and become a villain.
This is mainly due to his omnipresence and ambiguity in several important surviving mythological documents. Most accounts paint Loki as an apocalyptic, cunning, deceptive, quick-mouthed, scheming, shapeshifting troublemaker, thief, and trickster.
Here, holding on to all of the timelines, he became a kind of tree god, physically representing the Norse tree of life, Yggdrasil. It was a poignant and painful ending for Loki, who now seems to be sentenced to being alone for eternity as he watches over the timelines.
