There was lot to take in with the first Captain America: Civil War trailer, from the return of Bucky / Winter Soldier to the “accords” and the debut of Black Panther. Marvel introduced the first Phase Three film with a pretty detailed trailer, forgoing the usual vague teaser in favor of something far more meaty, and while you’ve probably watched the trailer a few times by now, there’s still some stuff you probably missed — and that’s where directors Joe and Anthony Russo come in, delivering lots and lots of interesting details.

The directing duo spoke with Empire in an extensive feature on the Captain America: Civil War trailer. It’s a long, great article that’s totally worth a full read, but we’ve picked out some of the biggest intel they shared. Let’s start with the Sokovia Accords, first hinted at by Cap during the Ant-Man post-credits scene and glimpsed briefly in the Civil War trailer. Joe Russo says it’s their version of the Superhuman Registration Act featured in Mark Millar’s Civil War comic, repurposed for the MCU:

We’re using the essence of what Civil War was about. The comic book isn’t applicable to the storytelling that we’ve structured up to this point, but the concept of registration, the notion that heroes need to be either monitored or controlled because their power can be scary, is applicable.

Joe adds that the Accords are the result of the climactic battles from previous films, which inspired the directors to ask, “If you could point to the collateral damage in all those incidents, could you use that against the Avengers to control them?”

The Accords are introduced by an old familiar face: William Hurt’s General Ross, who previously appeared in 2008's The Incredible Hulk, where he witnessed the potential dangers of super-powers when his son-in-law’s giant green alter-ego emerged. Joe says:

We thought it would be interesting to take a character who had a fanatical anti-superhero point of view. Now he’s become much savvier and more political and has put himself in a position of power, not unlike a Colin Powell. He’s cornering the Avengers politically now, he’s out-maneuvering them.

Not everyone is a fan of the Accords, of course, but they each have their own motives according to Anthony:

We wanted to figure out very personal reasons why everyone’s relationship to this idea of registration is going to become complicated. That’s what the relationship between Steve and Bucky allowed us to do, to get very personal in terms of why people would lean one way or the other.

Speaking of Bucky, the Russos explain that while the opening scene of the trailer is a continuation of the post-credits tag in Ant-Man, it actually takes place a bit later in Captain America: Civil War. The brothers reveal that much of the film is about Cap’s “fairly involved” journey to reunite with Bucky, providing ample space to explore their friendship. As for why they chose to open the trailer with that scene, Joe says that it was “the cleanest way to draw a line and highlight that this is Captain America 3, and not Avengers 2 and a half.”

And finally, Black Panther. Chadwick Boseman makes his MCU debut in Civil War, though Joe cautions that “he’s there for a very different reason,” and “his motivations are not their motivations,” referring to the rest of the Avengers. But what about that awesome costume? Joe explains:

It’s a combination of a practical costume and VFX. It’s a vibranium weave, a mesh, almost like a chainmail. Luminescence is something we have to do in post.

Joe and Anthony Russo reveal much more in the full feature over at Empire, including details on Crossbones, the relationship between Black Widow and Cap, and more.

Captain America: Civil War hits theaters on May 6, 2016.

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