The Iron Man-Thanos Relationship goes back to the original ‘Avengers‘ movie in 2012 when Tony Stark decimated his adversary’s (not Loki, he was just a stooge of Thanos) almost-fulfilled plan of destroying Earth. Interestingly, every other Avenger seemed to presume the New York episode as a dead-end of extra-terrestrial terror, and as a result, resumed with their normal lives. Except for Tony Stark!
One plausible explanation might be the fact that Tony witnessed the dread and true power of his nemesis by taking the nuke all the way into space. It was due to this that Tony Stark suffered from insomnia and PTSD, which drove him relentlessly towards building innumerous suits in ‘Iron Man 3‘. He knew it in his heart that the worst was yet to come. Sadly, he had to waste it all for the Mandarin (the real one).
Let’s jump to ‘Avengers: Age of Ultron’ now, another movie depicting Tony’s anxiety of impending doom as he built Ultron. As one may call it a classic Frankenstein sequel, Ultron turned out to be an aggravated form of Thanos, desperate to wipe out the entire humanity and not just half of it. Clearly, the crux of these movies revolved around Tony’s insecurity of Thanos (as in, a threat of such magnitude). Thanos mirrored Stark’s similar megalomania which led to Ultron. Remember, before leading a planet-hopping genocidal army, Thanos attempted to save his own planet due to the visions he saw of it being in ruins but was unable to ultimately save his planet. Tony too, had his fair share of failure as regards the Ultron-initiative.
It was only in ‘Avengers: Infinity War’ that Tony and Thanos met face to face for the first time, and the strange bonding between the two could be witnessed. Thanos seemed to have immense respect for Tony, as he said: “You are not the only one cursed with knowledge”.
Looking back at ‘Avengers: Infinity War’, Tony Stark was the only character Thanos made a true effort to kill (exempting the required sacrifice of Gamora) since murdering Loki in the first scene. Clearly, he was aware of Tony Stark’s capabilities.
Amidst all of this, we couldn’t help but admire how similar they were. Stark was that one person who could’ve stopped Thanos from fulfilling his goal, and that’s why the battles between the two characters feel so brutal and strangely personal. They both believed they had been chosen, in some way, to save everyone else. And they are each other’s biggest obstacles to achieving that goal. They were both futurists like none other. Thanos took up a parental responsibility of the entire universe, but his ideas of achieving the same steeped into violence and brutality. Tony took up a parental responsibility of his planet and in the end(game), he made sure that his responsibility prevailed, even at the cost of his life.
Last, but not the least, Tony Stark and Thanos are extremely stubborn and like to do things their own way, and one could describe them as iron-willed. Tony has time and again made it clear that he doesn’t particularly like being ordered around. He’s a person who attempts to do what they think is right, much like Thanos. The Mad Titan watched his planet die, which led to his desire to wipe out half the universe, and let’s not deny, he enjoyed a fair share of success for his crazy (or for the pessimistically misguided ones, ‘visionary’) plan. Clearly, both were a ‘messiah’ in their own way.