It all came down to a scrum for the Infinity Stones between Thanos and Iron Man. Although Thanos thought he had the upper hand, Iron Man secretly took the Infinity Stones to perform a snap of his own – one which wiped the Mad Titan and his army from Earth but also ended his own life.
In the 2019 film Avengers: Endgame, Iron Man (Robert Downey, Jr.) steals the infinity stones from Thanos and transfers them to his own suit. When Iron Man snaps, he gets rid of Thanos's army, but this action kills him.
He died by sacrificing himself for the good, of those he loved. He knew he wouldn't survive, but he did it anyway…the act of a true hero. While playing this role, this scene allowed Robert Downey Jr to give us some of his strongest acting in the MCU, even earning the words of Joe Russo saying he deserved an Oscar.
The Infinity Gauntlet - Thanos Kills Iron Man (1991)
In the comics, not as many Avengers survived and it was Silver Surfer and Adam Warlock that resurrected the dead. Not only did different people die with Thanos's snap, but Iron Man was killed even before that.
Avengers: Endgame writers Cristopher Markus & Stephen McFeely on why Iron Man was killed off? Because it legitimizes the whole thing. If you just keep going until it peters out or you lose interest, it kind of decays backwards, making (people) think less of everything that came before.
Iron Man Probably Won't Be Back
Bringing Tony Stark back would be a mistake because his character arc is already complete, from a successful billionaire who ran his company named after his father, to a superhero who made it his top priority to protect the world from dangerous threats and weapons of mass destruction.
Tony Stark died sacrificing himself for the greater good. While wearing the Infinity Gauntlet, he snapped his fingers, causing Thanos and his army to disintegrate before they could destroy the universe. As he did so, Tony knew full well that he couldn't survive such a burst of energy and would disintegrate as well.
After briefly experimenting with a telepresence suit, Tony created the War Machine suit to protect himself. He again faked his death and put himself into suspended animation, passing the War Machine suit along to Rhodey, who continued in his stead.
Thor, the god of Thunder, was undoubtedly the most powerful member of the original Avengers. His power continues to grow in the Marvel Cinematic Universe.
Iron Man Made the Ultimate Sacrifice to Defeat Thanos
In the culmination of the battle, Thanos retrieved the Nano Gauntlet and the Infinity Stones. He snapped his fingers but to no effect. Tony Stark had ripped the stones off the Gauntlet and attached them to his own suit.
At the end of the war, Tony Stark falls into a coma while fighting Captain Marvel, spurring Riri into continuing his legacy as a hero. With the help of an AI duplicate of Stark, Riri designs an improved suit of armor and takes on the name of Ironheart.
Imagine, Tony survived after End Game, he could have his own replicated Pym particles, had a time machine in his suit and even had access to each timeline in the multiverse. Dr. Strange believed if Tony Stark survived then sooner he will be the most powerful being in the universe.
The crux of the movie is Tony Stark searching for a replacement to palladium in his chest piece, which is poisoning him. Rhodey's iron man armor runs from an arc reactor not implanted in his chest.
In the aftermath of Civil War, Captain America is taken into S.H.I.E.L.D. custody where he is assassinated per the order of the Red Skull. Crossbones snipes at him while Sharon Carter, who has been brainwashed by Doctor Faustus posing as a S.H.I.E.L.D. psychiatrist, delivers the killing blow.
Story highlights. Tony Stark died at the end of 'Avengers: Endgame' but before that he saved the entire universe from Thanos and his forces by snapping them out of existence and ending their threat once and for all.
Thanos died for the first time in ”The Garden”, where the Avengers caught him off guard and Thor chopped his head off. He died for the second time when Iron Man used the Infinity Stones and turned Thanos and his whole army into ashes, sacrificing himself in the process.
DC & Marvel's Crossover Universe Made Hulk the Weakest Avenger - IMDb. The Hulk has been called the strongest Avenger given his unparalleled, planet-shattering strength, but within the 2099 future of Marvel and DC's crossover universe, the Hulk would be considered the weakest Avenger (for one specific reason).
Hercules / Zeus
He ranks above Thor here because he's technically the stronger of the two. In fact, he is considered by many authorities to be the physically strongest character Marvel has ever created.
The origins of Superior Iron Man would begin in the Axis event, in which the morality of Earth's heroes and villains was reversed by magic. While the spell was undone the now corrupt Tony managed to shield himself and thus retained his evil personality even as most of Earth's heroes reverted back to their usual selves.
Iron Man's death is final
Unlike in Infinity War, the deaths in Endgame were final. That's one reason why the MCU is so amazing.
Black Widow sacrificed her life for others in Avengers: Endgame, and Hawkeye just gave her death even more meaning in the Marvel Cinematic Universe. Warning! The following contains SPOILERS for Hawkeye.
The arc reactor keeps Tony Stark alive. In the different versions of Iron Man, Stark's group has been ambushed in Vietnam, the Persian Gulf, and Afghanistan. Stark sustained serious injuries as a result. He created the personal arc reactor to generate energy for an electromagnet keeping shrapnel away from his heart.
Tony's funeral is well-attended, and the camera swoops through the crowd past several groupings of characters: Pepper Potts and their daughter, Morgan; Black Panther, Shuri, and Okoye; Peter Parker, Captain Marvel, Nick Fury, the list goes on...it's an impressive gathering of superhero characters.
So, when Tony Stark died in Avengers: Endgame, people cried their hearts out because they saw their favourite character breathe their last in the movie. They realised that they won't be able to see Iron Man anymore. It was the end of an era for them, which explains the people's outburst regarding his death in the MCU.