Thanos destroys everyone and everything on the ship. He takes the Tesseract (which has an Infinity Stone inside) from Loki and then chokes the god of mischief until he dies.
So far, that was the only film in the trilogy where Loki didn't "die." His final, final death came at the hands of Thanos in Avengers: Infinity War. Loki's parting words to Thor were, "the sun will shine upon us again." And it has, but in separate universes!
In Thor 2 Loki seemingly dies with a green skin colour and turns out to be alive after. Many theories suggest that Loki faked his death in Infinity war as well, so that might be a reason we never saw Loki turn blue when Thanos killed him.
The movie kicks off with Thanos decimating half of all surviving Asgardians and their allies, including Heimdall and Loki. Loki tries to use his abilities as a trickster god to turn on Thanos and kill him, but Thanos quickly stops his arm and breaks his neck.
Loki. Of course, it just had to be a betrayal. After Loki seemingly joined Thanos and handed over the Tesseract, he tried to kill the Mad Titan by putting a knife right between his eyes. Unfortunately for the God of Mischief, Thanos had it scouted well in advance, and choked him to death.
The theory posits Ego, Odin, and The Ancient One as three of Thanos' greatest fears, and he waited until all of them were dead to make his move. This would make sense, as all of these characters were massively powerful and had strong ties to the Avengers, which meant they could be called in for backup at any time.
Thanos would have given the Mind Stone to Loki so he could test how the inhabitants of Earth defended themselves, but to their surprise, their attack triggered the creation of the original Avengers team, making way for Thanos' biggest enemies in the MCU.
Crucially, Loki's final words to Thor were: "I assure you, brother, the sun will shine on us again.” It's a poetic sentiment, but it may also be a direct link to Thor harnessing the power of a dying sun to make Stormbreaker.
Marvel Comics gave fans a peek into the true motivations behind Thanos' actions, confirming that Loki knows more about Thanos than the MCU does. In a recent peek into Thanos' true motives behind his villainous actions, Marvel Comics confirmed that Loki knows the Mad Titan better than his own MCU movies.
Even when he was power-hungry and arrogant, Loki was smart enough to know to fear Thanos. He was familiar with Thanos' past planet cleansing, and that is why Loki believed he was key in ruling Earth.
What if Loki didn t take the Tesseract in Endgame?
If Loki had left the Tessaract, the Tessaract would break, but the space stone would drift for anyone to take it among the debris. The stones are linked you have one, you can easyer find the other once. Thanos and probably also Maw could sence Loki had it.
He was under the influence of the Mind Stone that was in the Scepter, as were the Avengers in that scene where they were all sniping at each other. But Loki had been under the influence longer, and he had such a deeply rooted hatred and desire for revenge, it affected him more. Both for sure!
It was explained in “Thor” why he adopted Loki as a son. (SPOILERS from “Thor: Ragnarok” are below, so read at your own risk!) Loki was a helpless baby left to die in the cold, harsh environment of Jötunheim. Odin took pity on him and rescued him.
Loki has always delighted in cheating death, manipulating others into believing he was dead in order to hatch his next scheme. At the end of Thor, he apparently took his own life — but Loki survived death by plunging into one of the many portals he knew could be found in Yggdrasil.
The attempt ultimately was unsuccessful, however, as Thanos had destroyed the Stones to avoid temptation, rendering the goal impossible. Thor settled for the hollow victory of killing the Mad Titan out of revenge for the deaths of the victims, effectively ending the Infinity War.
After a couple of years, Classic Loki attempts to leave his isolation only for the TVA to be alerted and for him to be taken in as a variant. This clearly shows us that in the Sacred Timeline Loki survived Infinity War and has been living on this unknown planet for the past couple of years.
Thor knew that Loki was alive and on Earth not because of Heimdall… because of Frigga. In the comics version of The Movie Thor (2011), it is noted that Frigga communicated with Loki and warned Odin & Thor that the God of Mischief is alive and well. Hope this helps.
Thanos only kills that pose a threat at the moment (e.g. Loki and Heimdall). Thanos views everyone as being reasonable and doesn't expect people to agree with his 1/2 the universe ideology, which is why he'll let Thor play the lottery and survive or die later.
He whispered the words of the enchantment that was thereafter inscribed on the hammer: “Whosoever holds this hammer, if he be worthy, shall possess the power of Thor.” His intent was to give Thor a way to get his suppressed powers back once he learned his lesson.
Originally there was no restriction placed on the hammer for who can use it but after Thor's reckless behavior, Odin Borson placed an enchantment on it. This spell read "Whosoever holds this hammer, if he be worthy, shall possess the power of Thor." Only those deemed worthy to lift Mjolnir can.
Odin takes Thor's hammer Mjølnir and uses it to channel a burst of Odinforce that broke apart Thor's armor and pushed him into the Bifrost. After Loki angrily yelled at his adoptive father for not informing him of his true nature, Odin collapsed in shock.
In The Avengers, Loki tried to mind-control both Hawkeye and Iron Man, but while he succeeded with Hawkeye, his attempts failed on Iron Man due to his arc reactor. Iron Man's arc reactor protected him from Loki's scepter, as the scepter needed to touch organic matter to work, and the arc reactor was not skin.
Thanks to the augmentations afforded by his Kree warrior armor, Ronan survived direct contact with the Power Stone before giving it a new housing. Despite his heightened resistance to the Power Stone, Ronan is only shown holding it for under a minute before embedding it in the Cosmi-Rod.
Originally Answered: Why didn't Loki use the Tesseract against Thanos on the Asgardian ship? At the time, Thanos only had one Infinity Stone, and the Tesseract should have been able to hold its own against him, especially with the help of Thor and the other Asgardians. Simply because he doesn't know how.
