Here's everything you need to know about the new Captain America from the first episode of 'Falcon and the Winter Soldier'

Warning: This post contains spoilers for the first episode of The Falcon and the Winter Soldier

The Marvel Cinematic Universe has a new Captain America at the end of the first episode of The Falcon and the Winter Soldier… but it isn’t Sam Wilson… or Bucky Barnes... or Steve Rogers. Early on in the season premiere of Marvel’s latest Disney+ series, “Uncle Sam” (Anthony Mackie) surrenders the Vibranium-laced shield bequeathed by an elderly Steve (Chris Evans) at the end of Avengers: Endgame to the Smithsonian. But the U.S. government isn’t about to let that important a symbol lie in state. Instead, the Department of Defense handpicks its own successor, and introduces him to the world as Captain America while a shocked Sam watches on television from his sister’s home in Louisiana.

So who is this new Cap? While his identity isn’t given in the episode, it has already been disclosed in advance via featurettes and press materials. You’re looking at John Walker, played by Wyatt Russell — son of Goldie Hawn and Kurt Russell, who also has a role in the MCU as Star-Lord’s dad, Ego. Introduced into Marvel Comics continuity 35 years ago in 1986, Walker actually began his superhero career as the Captain American antagonist Super-Patriot, who felt that the star-spangled Avenger wasn’t properly representing the stars and stripes. One year later, a less reactionary Walker took up the mantle when Steve decided he was “Captain America No More.”

But Walker’s tenure proved short-lived: when his secret identity was leaked to the public, he retaliated against his enemies with extreme prejudice. At that point, Rogers reclaimed his old costume and the government’s Commission of Superhuman Activities arranged to fake Walker’s death. But he didn’t stay out of the costume game for long: in 1989, he reappeared as U.S. Agent, sporting the same Cap-inspired costume that Russell wears at the end of the Falcon and Winter Soldier premiere. Walker’s run as U.S. Agent continues today, and the rehabilitated hero has fought alongside the West Coast Avengers and Force Works.

For obvious reasons, MCU fans weren't thrilled to see someone other than Sam or Steve carrying the Captain American shield and let their outrage be known on Twitter.

Some also noted that Walker doesn't exactly have the most heroic jawline. And he certainly doesn't have America's ass.

It should be noted that Walker has a tangled comic book history with Sam Wilson that the FAWS writers are clearly drawing on for the series. After Sam became Marvel's Captain America in 2014, certain forces within the government urged Walker to replace him, believing that he lacked the necessary public support to continue on in the role. Underlying their criticism was the fact that Wilson was also the first Black man to carry the shield, and the comics frequently addressed the issues raised by his specific background. In an interview with Yahoo Entertainment, Mackie spoke about how race would inform the show as well. "This show deals with a lot of baggage that we harbor as Americans. It’s dealing with economic structure, race and not only the idea of being an American but being a human.”

Wilson's Cap and the U.S. Agent do eventually exchange blows in the comics, and a confrontation seems almost certain to happen during the six-episode run of the series as well. And it's already clear where social media's allegiance lies.

Besides introducing a new Captain America, the first episode of FAWS also establishes a new world order. Ever since half of humanity returned from their five-year Blip, nations around the world have been struggling to readjust economically and politically. One of the reasons the U.S. government rushes to nominate Walker as the new Captain America is to push back against the global "unrest that has left us vulnerable." Meanwhile, a group calling themselves the Flag Smashers are looking to erase any and all borders, believing that life was better during the Blip. That name is derived from a Marvel Comics villain that's been smashing flags since the 1980s. For now the group's aims seem clear and even understandable to some viewers. But it's still possible that the whole group is a smokescreen for the show's Big Bad: Helmut Zemo, who previously orchestrated the destabilizing events of Captain America: Civil War.

While Zemo doesn't appear in the premiere, the episode does feature the returns of some other familiar faces, starting with the hero who makes up the second half of the title. Much of the secondary plot is devoted to catching up with Bucky (Sebastian Stan) as he tries to confront and overcome his traumatic Winter Soldier past with the aid of a psychiatrist. We also see the re-introduction of Batroc, aka Batroc the Leaper (played by MMA fighter Georges St- Pierre), a longtime comic foe of Captain America who originally appeared in the opening sequence of Captain America: The Winter Soldier.

Last, but certainly not least, Sam has a poignant moment with fellow former Avengers, James "Rhodey" Rhodes, aka War Machine (Don Cheadle). Visiting the Smithsonian's Captain America exhibit, both men bond over feeling out of place in the post-Blip world... and the loss of their mutual pals, Steve and Tony Stark. Consider this a prelude to Rhodes's own Disney+ spinoff — the upcoming Armor Wars.

The Falcon and the Winter Soldier is currently streaming on Disney+

Read more from Yahoo Entertainment

• 'Falcon and Winter Soldier' team on rebooted Captain America: 'What does it mean for a Black man to pick up such an iconically white symbol?'

• First 'The Falcon and the Winter Soldier' trailer features bickering heroes and the return of a 'Civil War' bad guy

• New Captain America Anthony Mackie criticizes Marvel's diversity efforts: 'In no way, shape, or form is it enough'