Following the release of the Captain America: Civil War trailer, the Russos were on hand to explain the friendship breakup between Tony Stark and Steve Rogers.

We had a lot of feelings after watching the Civil War trailer, which premiered Tuesday night on Jimmy Kimmel Live.

And so did everyone else. The Internet was blowing up with reactions to the trailer, which not only gave a lot more away than we were expecting, but also introduced a brand new idea: that the titular Civil War doesn’t start because of the Superhero Registration Act, like in the comics, but rather because someone is threatening Steve Rogers’ pal, his buddy, his Bucky.

Related: Hypable’s Hype Podcast dissects the Captain America: Civil War trailer

In the trailer (which we have analyzed in depth), Steve explains to Tony Stark (right before they engage in a deadly yet sexy three-way smackdown) that he’s doing this, “Because [Bucky] is my friend.” Stark’s heartbreaking reply? “So was I.”

Empire managed to get a hold of Civil War‘s directors (and heroes of the Marvel verse at large) Joe and Anthony Russo, and they had a lot of interesting commentary to help shed a light on the dynamics in the film.

‘Civil War’ is all about the characters

In a world full of empty action movies, it’ll be reassuring to know that the Russos, like all the best storytellers, developed Civil War with the characters in mind, not the plot.

“The way we went about it, it was about tracing what was going on with these characters,” Anthony Russo tells Empire, “and we would examine each character on a very personal level — how would they respond to the idea of registration? What stakes would they have in this issue? Why is it good or bad for them?”

And that’s why it makes sense to put Steve at the center of this mess. “You cannot have a character called Captain America without examining the politics of what that means, especially in this day and age,” says Joe Russo.

Who the hell is Bucky?

We were delighted to see how central of a role Bucky appears to have in Civil War. Not just because we love him, but because this means this isn’t, in fact, Avengers 2.5. Because if Bucky is the most important person to Steve, and his dilemma is at the center of the conflict, then this movie is all about Steve.

But did this trailer in fact represent Bucky’s importance to the story? The answer appears to be yes.

Anthony Russo reveals that in the first part of the movie, “There is a story about how Cap gets to Bucky, and that’s fairly involved.”

Related: Your Bucky: The most emotional Steve and Bucky moments

And after he finds him, and the beautiful memory scene that opens the trailer (which is “not early” in the film), we appear to move into a new story — about who Bucky is now.

According to the Russos, his memories are there, but they’re foggy. The movie will explore the question of who Bucky has become after having gone through brainwashing, and now having to face all the crimes he’s committed.

“How does that character move forward? He’s not Bucky Barnes anymore. He’s not the Winter Soldier anymore. He’s something in between,” Joe Russo says.

(It’s like every Winter Soldier recovery fanfic ever, basically.)

Tony Stark is doing the right thing, too

Why would Tony Stark, billionaire and grudging philanthropist, side with the government in the first place?

“Tony’s defining characteristic is his egomania, in a lot of ways,” Anthony Russo says, “and we thought it would be interesting to bring him to a point in his life where he was willing to submit to an authority, where he felt it was the right thing to do.”

Related: Robert Downey Jr.’s enormous 2015 salary revealed, is Iron Man still worth it to Marvel? (opinion)

It’s also his guilt complex which drives him, and he has a “very legitimate argument” for doing what he does.

His relationship with Steve, which the Russos describe as “a sick, complicated relationship,” is not founded on a decades-old friendship like in the comics. Rather, it’s tracking the parallel stories of these two heroes, who are both symbols of their time. In fact, their lack of history might make the conflict more clear.

They find each other on opposite sides, without enough knowledge of each other to fully understand their very personal reasons for acting the way they do.

So they might not be friends the way Steve and Bucky are friends, but their charged dynamic is certainly important, especially to Tony.

That helicopter scene is super important

Apparently it’s not just for memes, guys.

“He’s hanging onto that helicopter for an extremely passionate reason,” Joe Russo reveals (and we immediately assume Bucky is inside, of course!).

In fact, this scene, “really represented his struggle as a character, one man pitted against a helicopter that’s trying to take off. Can he stop it? And what are the limits of his strength? For us, it’s one of the most powerful shots in the movie.”

What the hell’s in that thing? If not Bucky, could it be Sam? Natasha? Something related to Peggy Carter? We’ll have to wait and see…

There is a lot more to take away from Empire’s incredible interview, including an elaboration on Black Panther’s armor. So make sure you read the whole thing to find out what drove Joe and Anthony Russo to tell the story of Civil War.