David Harbour Teases Red Guardian’s Feud With Sam Wilson in ‘Avengers: Doomsday’, and Alexei Is Already Trash-Talking Captain America

Red Guardian has always believed he is a bigger deal than anyone around him gives him credit for. Since his debut in ‘Black Widow’, Alexei Shostakov has bragged about his glory days and his supposed battles with Captain America, and fans have loved every ridiculous boast. Now, a new tease from the actor behind the character suggests that rivalry may finally come to a head in ‘Avengers: Doomsday‘.

David Harbour made the remarks while speaking to fans at Comic Con Liverpool, where he previewed the dynamic between Red Guardian and Sam Wilson. The details were short, but they were enough to get Marvel fans talking.

According to reports from the convention, Harbour said that Red Guardian genuinely believes he is as great as Captain America. In his mind, there is no doubt that he could take Sam down, and he used a particularly dismissive insult for the current Cap in explaining it. The sources I found for the quote were secondhand, and I could not locate the original panel footage, so it’s best to treat the exact wording with caution.

The joke fits the character perfectly. Alexei is a man whose confidence far outweighs his credentials, and the idea of him sizing up Anthony Mackie’s Captain America is exactly the kind of comedy fans have been hoping for.

The seeds of this feud were planted in 2021. In ‘Black Widow’, Red Guardian repeatedly boasts about fighting Captain America, and Harbour himself leaned into the idea at the film’s virtual press conference, joking about a Red Guardian versus Captain America movie and calling out Kevin Feige. Feige later teased fans when he was asked whether Red Guardian would ever fight Sam Wilson.

That playful back-and-forth has now been woven into the larger Marvel story. Mackie’s Sam Wilson has become the new Captain America, which gives Alexei a fresh target for his bravado.

The tension isn’t just personal. Red Guardian is now part of the New Avengers, a group that also includes Bucky Barnes, Yelena Belova, Ghost, John Walker and Red Guardian himself. In ‘Avengers: Doomsday’, they will have to share the stage with the original Avengers, whom Sam Wilson is reportedly trying to rebuild.

Harbour told Entertainment Weekly at San Diego Comic-Con that there is trouble for sure between the 2 groups. He explained that the New Avengers believe they are making the right choices, while others may not agree with their methods. Their approach to saving the world is simply different.

He used to be different. Avengers: Doomsday arrives in theaters everywhere December 18. Get your tickets now: https://t.co/J5PUbxvAkc https://t.co/OUutSMZneq

— Marvel Studios (@MarvelStudios) August 15, 2026

This isn’t the first time Harbour has dropped tidbits about the film. In an interview with Variety, he was asked to recite a line from the movie and responded, in Alexei’s Russian accent, by pointing and saying the words “You are Tony Stark.” That sparked a flurry of theories about Robert Downey Jr.’s Doctor Doom, though it may simply have been a joke.

He also told Deadline that the film will affect the bond between Red Guardian and Yelena, and he has hinted at a bromance between Red Guardian, Winter Soldier and US Agent. At Rose City Comic Con, he praised the film’s scale and compared it with ‘Captain America: Civil War’ and ‘Avengers: Infinity War’.

‘Avengers: Doomsday’ arrives on December 18 and is directed by Anthony and Joe Russo. Downey stars as Doctor Doom, and the cast includes heroes from 3 universes, including the Avengers, the X-Men and the Fantastic Four. Footage has shown the Avengers, New Avengers and Fantastic Four gathered in a single meeting room, which hints at the tension that Harbour is describing.

Harbour also appeared at San Diego Comic-Con Málaga in October alongside Mackie and Winston Duke, where the cast joked about the film’s destructive scale. The shared appearance suggests that, off screen, the actors have a warm friendship, even if their characters may be at odds.

For many viewers, the beauty of a Red Guardian and Sam Wilson feud is how low the stakes feel compared with the film’s multiversal threat. In a movie packed with galaxy-ending drama, a petty argument between a self-proclaimed legend and the official Captain America offers a welcome dose of humor. It also gives Harbour another chance to steal scenes.

Of course, it remains to be seen whether the feud will turn into a full fight or stay a running gag. Either way, fans will get their answer in December.

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