In Black Widow, Red Guardian claims he fought against Captain America, and it seems possible because of Avengers: Endgame. Marvel's Black Widow finally introduces part of Natasha Romanoff's (Scarlett Johansson) backstory. Long before she was Black Widow in the Avengers movies, young Natasha was part of an undercover Russian spy operation in the United States in the '90s. There, she posed as part of an ordinary family living in Ohio, with Yelena Belova (Florence Pugh) assigned to play her sister and Alexei Shostakov (David Harbour), a.k.a. the Red Guardian, and Melina Vostokoff (Rachel Weisz) assigned as her parents. After the mission, the Soviet-Russian Red Room brings in Natasha and Yelena for more brainwashing and training.

In Endgame, Captain America (Chris Evans) goes back in time to return the Infinity Stones, but things don't go as planned. Instead of returning to the main timeline, Cap decides to stay in the past after replacing the Infinity Stones, living a secret life with Peggy Carter (Hayley Atwell). After all, that was the life taken away from him when he became frozen under ice in Captain America: The First AvengerAn older Cap then appears in Endgame, passing on his shield to Sam Wilson (Anthony Mackie).

Related: Avengers: Endgame Theory – Natasha Sacrificed Herself To Save Yelena

Red Guardian says multiple times in Black Widow that he fought Captain America, and theories say it may be true. In a scene in prison, Red Guardian is arm wrestling and claims he fought Cap in the '80s. When a fellow prisoner questions the story, saying Captain America would've still been frozen during that time, Red Guardian breaks his wrist. Later, Natasha and Yelena break Red Guardian out of prison, and he eventually brings up Cap to Black Widow, asking if Steve Rogers ever mentioned him. Though Rogers was in the ice during the '80s in the main MCU timeline, there's a chance Red Guardian isn't lying about Captain America, and it's all because of Endgame.

Red Guardian Captain America

There are a couple of options for how Red Guardian could've fought Captain America. In Endgame, Captain America's time-traveling trip to return the Infinity Stones isn't necessarily a precise process. He could've made a detour in the '80s, briefly fighting Red Guardian. Also, Cap's life with Peggy is still a big unknown. Though he was supposedly laying low, Captain America could've secretly fought crime during that time. If that's the case, he would've been around his 70s when he fought Red Guardian. After all, Red Guardian probably wouldn't have asked Natasha about Cap if it weren't true.

Red Guardian's story could be something else. Kevin Feige addressed the Cap and Red Guardian conversation on Twitter during a Black Widow watch party, saying, "Good question.. Although, wasn't Captain America frozen in ice then?" The comment hints that there's something more going on with the Cap and Red Guardian fight. Of course, Red Guardian likes to embellish stories from his glory days, so it's hard to believe anything he says. But because of time traveling in Avengers: Endgame, even Red Guardian's anecdotes are possible.

More: Black Widow Wasted Taskmaster’s Unique Fighting Ability

Key Release Dates