Let’s go back to 2012’s The Avengers when Captain America accused Iron Man of not being the kind of guy to lay down and let his colleagues walk over him to get to safety.
Even though at that moment Iron Man was pompous in his answer by saying, “I think I’d rather just cut the wire”, in truth, he has been the one putting his life on the line ever since the beginning, both teasing and escaping his death in every single Avengers movie.
When Loki and his army were laying waste to New York, the top people at SHIELD decided the only way to avoid the spread of Loki’s menace was to blow Manhattan to smithereens along with the tesseract and all the innocent civilians the original members of The Avengers had spent the better part of the day saving.
Iron Man took it upon himself to carry the nuke straight into the portal to end all the Chitauri once and for all. On his way there, Jarvis warned him that it was most likely a one-way trip, but he didn’t stop. And if the force of the blast hadn’t pushed him out of the portal just in time before Black Widow closed it, he would have been sealed, caught in the blast, and died as early as the very first Avengers movie.
Avengers: Age of Ultron
Cue Ultron and his army trying to destroy the whole world and remake it in his own machine image. Though Tony Stark had a personal stake and fault in this because he was one half of the genius duo who created Ultron in the MCU (Hank Pym created Ultron in the comics), he took it upon himself to destroy the bigger part of the Sokovia meteorite that was about to crash land on earth and bring about global extinction.
Destroying it meant he had to heat up the vibranium core long enough for Thor to hit it with so much force, that it would create enough vibrational energy to destroy all the rocky material it was holding. And who was right under the falling meteorite? Iron Man.
Just before he started heating it up, he told Thor that he might not make it out alive, and once again, he only did by the skin of his teeth because all the rocks, the giant vibranium pipe and core almost crashed on him as they scattered in the waters below.
Avengers: Infinity War
The Mad Titan had had enough of everyone failing to destroy Earth and he took it upon himself to succeed where Loki and Ultron failed. A makeshift team of The Guardians of the Galaxy, Iron Man, Spider-Man, and Doctor Strange went to Titan to fight Thanos themselves.
As a team, they were barely holding it together and didn’t make a single dent on Thanos, and the only person who could have faced him in a one-on-one battle without it looking like suicide was Doctor Strange. But then again, who stood up to do so? Iron Man.
He was the only one to draw blood from Thanos, who respected him for it, only after running Iron Man’s own blade through the billionaire playboy’s guts. He would have died too, if not for the nanites he incorporated in his suit to repair his damaged tissues just like how Hawkeye was healed in Age of Ultron.
The last and final piece of Tony Stark sacrificing himself and finally making good on all the teases he’d been doing from the beginning. After Thanos had brought himself to the present and had taken out their most powerful weapon – Captain Marvel -, the gauntlet had finally gotten into his hands again and the only way for him not to snap them all out this time, was for Iron Man to steal the infinity stones from right under his nose, incorporate them into his own bleeding-edge armour and snap Thanos and all his armies out of existence, only this time, the act really did cost him his own life.
Iron Man had been laying down for his colleagues and others to walk all over him from the beginning, he had been sacrificing himself time and time again to save everyone, and had no doubt been the most influential avenger between phases 1-3 of the Marvel Cinematic Universe, even though he had not been getting the credit for it.
Iron Man, we love you 3000.