When it came time to team up characters for Avengers: Infinity War, writers Christopher Markus and Stephen McFeely sought a balance between delight and terror. What made Marvel Studios' concept of a shared universe so enticing was exactly what's made it so appealing for decades in the comics: the ability to pair together characters who stood as titans on their own. The Avengers and its critical and financial success proved that even non-comic fans were ready for such an idea, and the new trailer for Avengers: Infinity War offers a tease of how surreal it will be when the Guardians come to Earth.

Beyond just the Guardians of the Galaxy and Avengers meeting, Avengers 3 will pull together plenty of other heroes who have never met. Thor and Hulk have both been off on their own mission, and very few people know Doctor Strange. Then there's the fact that the third act of Avengers: Infinity War takes place in Wakanda, meaning the characters of this year's hit film and the fantastical nation will be revealed to a number of people.

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During Screen Rant's set visit for Avengers: Infinity War in June 2017, our own Rob Keyes heard from writers Christopher Markus and Stephen McFeely (returning from the Captain America trilogy and penning both Avengers 3 and 4) about how the process of pulling together dozens of characters worked. And unsurprisingly, the framework of Captain America: Civil War was a key starting point.

Stephen McFeely: I don’t know if we can tell you what the pairings are but yeah, one of the goals… After Civil War, we got in a room for 4 or 5 months trying to crack these two ridiculously big things.

Christopher Markus: We had wall of characters and at a certain point you just go [motions hands] - “That’s funny and that’s funny. What’s a story that could get those two [characters] together?”

Markus and McFeely debated whether any of the pairings in Avengers: Infinity War would surprise audiences, but they certainly hope to achieve that. But beyond mere shock, the idea that drove the match-ups in the movie was more a desire to explore what would be revealed when putting two disparate characters in a room together and watching them play off one another.

McFeely: Right. We talked a lot about, it’s a [co-director] Joe Russo term, “strange alchemy.” What is it when you put the two characters together, even in a fairly normal traditional situation, but since we’ve invested in those characters and known them, we sort of delighted in the idea of those two people rubbing against each other. So, we always chased “delight” – and terror. Lots of terror.

Markus: And there’s also…we’re coming off Civil War. We’re coming off Winter Soldier. So that there’s lots of backstory that still needs to play out in addition to the Thanos situation. Like, I just walked by Sebastian Stan out there. You could put Bucky in a room with anybody and they’re going to say, “Oh sh*t! He’s a maniac.” He’s shot Natasha [Romanoff] twice as far as I can keep count, so it’s going to be interesting.

The discussion of Captain America: The Winter Soldier and Captain America: Civil War is especially interesting, as those are the two previous films Markus and McFeely have written. Though each ramped up the level of superheroes involved, jumping to Avengers: Infinity War and Avengers 4 was quite something when compared to the more grounded Steve Rogers stories.

We've had hints of what the pairings will be in the new film, especially thanks to Empire's Avengers: Infinity War covers yesterday. But the new trailer in particular offered multiple mini-groupings (ie. Spider-Man and Doctor Strange) that are sure to delight and maybe even terrify fans when Avengers: Infinity War lands in theaters.

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