Avengers: Infinity War has finally arrived and we need to talk about the relationship between Hulk and Bruce Banner. Virtually every major character from the Marvel Cinematic Universe, with a few notable exceptions, has a part to play in this massive movie and Mark Ruffalo's Bruce Banner has a very important one at that. However, those who have been following the character's journey throughout the MCU may have some questions about the progression that took place here, so let's dig into what went down and why it may have went down in just such a way.
Warning: major spoilers ahead for Avengers: Infinity War. This is your last chance to turn back. You've been warned. Just to catch up, the events of Thor: Ragnarok ultimately resulted in Bruce Banner on a trip back to Earth with the remaining Asgardians on the ship housing all of the refugees. Unfortunately, Thanos' ship comes upon them and he wants the Tesseract, which is in Loki's possession. Hulk does his best to give Thanos the whooping he deserves, but the big green guy is no match for the Mad Titan. For the first time ever, Hulk gets his butt handed to him in a fight in a big bad way. Heimdal, in his last act of existence before meeting his demise, sends Hulk to Earth to warn The Avengers of what's coming.
Once he crashes into Doctor Strange's Sanctum Sanctorum, Banner is back and Hulk has been sidelined. But from that point on, despite the fact that Banner tries to turn into his larger, angrier other self, he simply can't. Even when his life is threatened, Hulk won't come out. He even has to put on the Hulkbuster armor during the battle in Wakanda in order to be of some help during the fight. We don't see Hulk for the rest of the movie, which is particularly strange since there were shots of him in the trailers that didn't end up in the final cut of Infinity War. This happens from time to time in big blockbuster movies, but here it's of particular note, given the struggle Banner is going through.
While we don't really have an answer as to why these shots are in the trailers, or why those shots were filmed in the first place, we may have an explanation for why Hulk refused to come out to help defeat Thanos and the Black Order. As mentioned, Marvel's big green rage monster has never truly lost a fight. He would have been defeated by his friend from work in Thor: Ragnarok had Grandmaster not intervened, but Thanos could have killed Hulk had the fight not ended when it did. Taking that into account, it's quite possible that Hulk isn't coming out because he's scared.
Yes, it seems very much like Hulk, of all characters, is actually hiding inside of Bruce Banner for the time being because he's straight-up scared. Ever since Avengers: Age of Ultron, both Banner and Hulk have developed a lot more independently of one another and the struggle has become more fleshed out and intricate, as we see in Infinity War. There is no telling how this is all going flesh out in Avengers 4, but Bruce Banner made it through Thanos' genocide. Hopefully, Marvel will let Hulk have a rematch with the Mad Titan next year, if Banner can get the complex situation sorted out.