As a writer who seems to love asking questions and, then, possibly talking around answers without anything definitive, I just have to ask: why Iron Man? The opening scene of Thanos vs. Hulk #1 is a bit of banter set-up as Iron Man and Maria Hill view footage of Pip the Troll kidnapping Bruce Banner. Maria Hill, as director of SHIELD, is a given. She’s Banner’s boss and there’s no one who can replace her. But, the other party of the conversation is a little more open. So, again, why Iron Man?
“Because Jim Starlin wanted to use the character” is, of course, not an acceptable answer. It’s a no fun answer. We will set that aside and speculate all we want... Before we can establish why Iron Man was chosen, we should probably settle on other possibilities for his place in the scene. The requirements, as I can see them are: superhero, Avenger, someone familiar/casual with Maria Hill (or, rather, someone you buy having a conversation with her about Banner), someone who would want to know where Banner is, and someone familiar with Pip the Troll. That’s a pretty short list (although mine is by no means complete necessarily): Iron Man (duh), Captain America, Captain Marvel, and Hawkeye. You could maybe argue for Black Widow or Thor, but they seem like long shots to me. Out of the four candidates, Captain America doesn’t work for the light banter that the scene has. It doesn’t need that banter necessarily, sure, but using Captain America settles you into a more serious tone that the other three don’t require. Hawkeye would serve a similar purpose to Iron Man, except without the ‘fellow genius’ bit that Stark shares with Banner, stretching the believability of Barton caring where Banner is at all without inventing a reason. When Stark shows up, wondering where Banner is, a reason isn’t required, because we can all fill in that blank ourselves.
That leaves Captain Marvel. I’m a little surprised that Starlin didn’t use her as she’s a more obvious ‘cosmic’ connection character. And it’s a chance for him to use another character with that name. I’m not sure how chummy she and Hill are, but, in Hickman’s Avengers books, they’re at least both aligned with Steve Rogers, suggesting that they could be on friendly enough terms. Both are military women, both work with the Avengers... it’s not inconceivable (unless I missed out on it being established that they are friends or enemies somewhere...). She’s not as big a name as Iron Man, but that hardly seems to matter. There is something a little off about having two women introduce this plot and not actively be a part of it that is possibly best avoided.
There’s also the expectations raised by Starlin using Captain Marvel at all. If she wasn’t a part of the story later on, it would seem like a waste in many ways. Iron Man showing up for the first four pages of the story and never appearing again doesn’t let anyone down. Captain Marvel showing up would definitely have people wanting to see more of her and have Starlin spend a little time with his third Captain Marvel (I don’t think he ever really did much of anything with Monica Rambeau, while he did uses Genis-Vell in The Infinity Abyss and drew a few issues of his solo title). Suddenly, you’d just want Starlin to be doing a Captain Marvel cosmic story and wonder why he’s bothering with all that Hulk nonsense. Not the best reason to not use a character; it’s also not a terrible idea to avoid using a character that could change the story you want to tell so radically – or, at the very least, change how it is perceived. (Though, it’s also likely that people would just dig on Starlin drawing Captain Marvel for a few pages for what it is. Who knows with people... not I.)
Then, does Iron Man add anything else besides fitting the basic criteria of the scene better than any other character? He did have a recent turn as a member of the Guardians of the Galaxy, so, if he were to show up later in the story with that group as they look to rescue the Hulk, it would make sense. Given the timeframe of this story, it’s possible that he was still a member of the team at the time. Starlin could be taking advantage of the character’s newfound love of all things space. There’s also the natural chemistry between Stark and Hill; they have a long enough history that using them together is a decent method of shorthand and allows Starlin to write some banter in what could be a fairly dry opening scene. After all, it exist solely to introduce the plot of the comic.
Which leads us to our next question: why begin the comic this way?