Thanos simply turned to The Other and smiled, showing not only that he was willing to challenge them but it was also a nod to Thanos' relationship with Death in the comics.
By the time Infinity War comes around, he's gathering the Infinity Stones so he can do it himself and prove his theory right. He was ultimately victorious, devastating MCU heroes and fans alike (except for Bradley Cooper) in the process, which is why Thanos is smiling in Infinity War's final shot.
After Loki arrived on Earth and used the Scepter's power to build a small army of human soldiers, including Erik Selvig and Hawkeye, he went to a flashback where he was speaking to Thanos, with the Other being the one who was speaking with him on behalf of Thanos.
Josh Brolin is known for playing Thanos, but at the end of The Avengers (2012), in which Thanos appears in the post-credit scene, he is actually played by an actor by the name of Damion Poitier. Josh Brolin only got cast as Thanos in 2014, first portraying him in Guardians of the Galaxy.
Upon learning that Annihilus wanted to destroy all life in both the positive and negative matter universes, Thanos tried to release Galactus. Most unfortunately, Drax showed up and ripped out Thanos's heart, killing him.
When Gamora finally does confront Thanos, she believes for a moment that she's killed him and breaks down, crying. An orange light passes over her--but it's fleeting. Whatever love Gamora has for Thanos is all but smothered by darkness.
Thanos eventually realizes that all the trouble he went for in the snap: Killing Gamora, Killing Asgard's population, and ruining lives, have been for nothing. Thanos commits to finding a solution to reverse the snap. He starts to repair the gauntlet and confronts the Avengers.
Thanos simply turned to The Other and smiled, showing not only that he was willing to challenge them but it was also a nod to Thanos' relationship with Death in the comics.
Stark had had visions of death and destruction in Avengers: Age of Ultron and presumably before and after too, but the threat he sensed coming to the earth did not materialise in his mind in the form of Thanos, though he did know it came from the outer space. Thanos, though, knew who exactly Stark was.
Without the Infinity Gauntlet, Thanos stands little chance against Prime Odin. Odin is stated to be able to shatter the Earth. And he turned Frigga into stars. He has devastated while worlds, laid waste to kingdoms and destroyed demons and monsters.
“He's aware of Stark from the original Battle of New York as the person who undid the plan,” said Russo about Thanos knowing Stark. The makers also explained the connection between Stark and Thanos in regards to what they want to achieve: a path for a better future.
We know that Gamora wasn't at Tony Stark's funeral - unsurprising considering that she didn't know him, really - so she must have fled after the battle was won.
However, Red Skull saw his true intentions, informing Gamora that Thanos was, in fact, weeping for Gamora, as he truly loved her as a daughter, and was heartbroken that he had to sacrifice her to get the Soul Stone. Disbelieving, Gamora could not comprehend that Thanos ever showed genuine love for her.
How did the Russo brothers decide which Avengers would disappear in the snap in Avengers: Infinity War? They worked backwards. They had to have the original team because the plot was all about wrapping up their lives.
Another prevalent argument is that the God of Thunder was simply too exhausted at that point, having used all of his energy fighting Hela in Thor: Ragnarok.
Although in Endgame, they found and killed Thanos 2 weeks after he snapped half the Universe from existence,It would be another 5 years before they were able to Snap everyone back.
Thanos never cared much for Nebula, even going so far as to say in Guardians of the Galaxy that Gamora was his favorite. That could be because, to Thanos, Nebula was nothing more than a means to spare Gamora while still obtaining the Soul Stone.
Because she does not have a history with the Guardians, she does not reunite with them at the end of Endgame. Instead, she starts her own journey while Peter Quill is left mourning his dead girlfriend despite the existence of another version of Gamora in his universe.
As proven by Thanos sacrificing Gamora, he's a being capable of love. While he may not have had affection for Nebula in her adult years, her growth and ability to fight with 100 percent of herself every time were enough for him to pay attention to her and try and "help" her to ensure she never lost again.
Mjølnir: Thor was wielding the magical Uru hammer, which he had lost when he was banished from Asgard. However, before Thor could retrieve the Mjølnir from S.H.I.E.L.D., he was killed by Hawkeye.
Deadpool, who Thanos had once cursed to undeath in an effort to keep him away from his beloved Death, believed Thanos was to blame and attacked him onboard Sanctuary. Thanos consequently rescinded his curse, turning Deadpool into the only mortal creature in the universe, and killed him for the transgression.
After escaping to the Garden and destroying the Stones, he is eventually killed by Thor. Five years later, an alternate version of Thanos from 2014 time travels to 2023 to battle the Avengers once again, but is killed by Tony Stark.
