The movies of Marvel Comics are more or less related, not to mention the The Avengers series. Although there seems to be no connection between the first two films, in fact, the villain Loki in the first film was sent by Thanos to invade the earth, and Thanos also knew about the battle between Ultron and The Avengers in the second film.
Thanos was the villain behind the scenes, but because Loki was later stopped and the time was ripe, Thanos went to the front of the curtain to personally confront the members of The Avengers in order to find the infinite gems on the earth.
Thanos remembers that Iron Man first appeared in the first film of The Avengers, when Thanos sent a spokesman to let Loki invade the earth. In addition to giving Loki a scepter and a Rubik's cube, he also gave Loki a huge Zetatali army. In the first film, it is Ze Tatari Corps and Pig teammates who put the members of the revenge group into a bitter battle.
Loki opened the wormhole with a scepter, and Ze Tatari's army invaded the earth and fought with The Avengers members until they stuck together. Lawmakers decided to launch a nuclear strike on Manhattan Island to ensure that the Zetatari Corps was stopped. A nuclear bomb pierced the sky and went straight for the target. At this critical moment, Iron Man successfully caught the nuclear bomb and prevented civilians from being attacked by nuclear weapons.
Then Iron Man flew out of the wormhole with the nuclear bomb and went to Zetatali warship to detonate the nuclear bomb. The collapse of Ze Tatari Legion made Thanos realize Iron Man and expressed his expectation for Tony Iron Man.
Another point is that both Thanos and Tony Iron Man are cursed by knowledge. In the third part of The Avengers, Thanos once said to Tony Iron Man? Aren't you the only one cursed by knowledge? . Thanos was cursed by knowledge, which made Thanos not only have a strong body, but also have super intelligence. Powerful warships and weapons were also invented because of the curse of knowledge. Thanos knows the power of knowledge and pays more attention to those who are cursed by knowledge.
Thanos should have a list of people cursed by knowledge. At first, I didn't pay much attention to Tony Iron Man on the list, but after the battle in the first film of The Avengers, Thanos paid attention to Tony Iron Man. To say the least, because of Loki's failure, the Avengers organization on the earth has also been exposed. Thanos personally sent out to collect infinite gems, and he will also investigate the members of the Avengers organization in advance when preparing. After all, know yourself and know yourself!