David Harbour says he wants to do a Red Guardian movie where he seeks 'vengeance' for Black Widow's death

• Harbour told Insider about his idea for a Red Guardian sequel to "Black Widow."
• "Maybe the version of the story he hears is that Hawkeye pushed her off [the cliff]," Harbour said.
• It leads the character on a path of "vengeance," Harbour imagines.

In "Black Widow," the long-awaited Marvel movie that gives a standalone story to Avenger Natasha Romanoff (Scarlett Johansson), David Harbour plays Alexei Shostakov, who is the Russian version of Captain America, known as Red Guardian.

Shostakov is way past his prime. However, he still has a close bond with Romanoff as he was a father figure to her when she was a child.

Harbour believes that this bond could be used to drive forward a standalone movie for Red Guardian.

"When he finds out that she was on that cliff with Hawkeye and maybe the version of the story he hears is that Hawkeye pushed her off or something, it's a moment when Red Guardian turns back to the guy he was," Harbour told Insider. "He now wants vengeance for her. That I feel would play well."

Harbour is referring to the death of Romanoff in 2019's "Avengers: Endgame" ("Black Widow" takes place following the events of 2016's "Captain America: Civil War").

The truth is Black Widow and Hawkeye (Jeremy Renner) were both prepared to jump off the cliff on Vormir so the other could obtain the Soul Stone during the Avengers' time heist to save humanity. It led to them fighting to try to stop the other from having to jump. Finally, it was Romanoff who fell to her death.

But Red Guardian being told Hawkeye is to blame for Romanoff's death could lead to an exciting revenge story (or a subplot in the upcoming Disney+ "Hawkeye" series).

In the Marvel comics, Red Guardian was created by the Soviets during the Cold War and the persona was given to Shostakov, who was one of their best pilots during World War II. He goes on to battle Captain America.

The events in the MCU causes difficulties for the Red Guardian's comic-to-movie timeline as Captain America in the movies was frozen during the Cold War (fun fact: Shostakov is Romanoff's husband in the comics). But that could lead to a lot of fun.

Harbour describes Shostakov to Insider as a "narcissist," so you can only imagine the tales he will weave about his past in a standalone movie of the character.

"Black Widow" opens in theaters and available on Disney+'s Premier Access beginning July 9.