In Avengers: Age of Ultron, Banner and Hulk return to the big screen and Ruffalo spoke to Entertainment Weekly about how he is developing their respective characters.
"There’s a very cool thing happening: Hulk is as afraid of Banner as Banner is afraid of Hulk.
"[Y]ou haven’t really been able to get inside of Hulk’s head, because the [cinematic] technology wasn’t available to make it nuanced enough to do that, and now it is. So now I think there’s a way to do it. Both of these guys are obviously the same guy, and they have got to come to peace somehow with each other. And I think that this confrontation is building along the lines of this film. He’s terrified of [Banner].
"What makes Hulk afraid? It’s himself. It’s a version of himself that’s weak. It’s a version of himself that’s vulnerable. It’s a child inside of him. It’s very interesting, and I’m stumbling on this. And I don’t know if this is where the next version will go. But if it is in the cards that we’re doing the next version of this, I see some fertile ground there."
By not having his own solo Hulk movie, like most of his Avengers comrades in Phase 2, Ruffalo has been able to think a lot about where he wants to take Banner and Hulk in Avengers: Age of Ultron and beyond to Phase 3.
"I’ve been mulling this over now for a few years. And I haven’t pushed for it because I honestly didn’t know what hadn’t been done. And this time, there’s an interesting confrontation on the horizon between these two."
"On the horizon" is a little teaser clue. Could this confrontation between Banner and Hulk boil to something so terrible the Hulk becomes a threat to his teammates and Earth? Fans will have to wait for that answer. Until then, Hulk is set to smash next summer.
Avengers: Age of Ultron is currently filming in the U.K. and is set to release on May 1, 2015