Could Captain America 4 Be The First Introduction Of Dr. Doom?

"Captain America: New World Order" signals a changing of the guard with the first solo outing of Anthony Mackie as the Star Spangled Man with a Plan. Following his journey to accept the shield and the mantle in "The Falcon and the Winter Soldier," Sam Wilson is set to go up against Tim Blake Nelson's Samuel Sterns, aka the Leader, who is returning to the Marvel Cinematic Universe for the first time since his lone appearance in "The Incredible Hulk." Sterns isn't the only "Incredible Hulk" character who will be featured, however; "New World Order" will also see Harrison Ford's debut as the recast Thaddeus "Thunderbolt" Ross and the long-awaited return of Liv Tyler's Betty Ross, giving fans plenty to look forward to.

Another interesting character cast in the upcoming film, Diamondback (Rosa Salazar), could provide us with a peek into the introduction of one of the biggest villains in all of Marvel Comics: Dr. Victor von Doom. While multiple people have carried the mantle of Diamondback in the comics, one of them, Deborah Bertrand, has a connection to Lucia von Bardas, the Prime Minister of Latveria under von Doom. And although there is no word yet on either of those characters showing up in the film, the presence of Diamondback does open the door for a number of Easter eggs to plant future appearances.

In the comics, Lucia von Bardas hires Deborah Bertrand and Scorcher to kill Matt Murdock in revenge for Nick Fury's attack on Latveria. However, there's also another character who goes by the name Diamondback: Rachel Leighton, who is a former member of the Serpent Society, having changed her ways when she fell in love with Captain America.

What makes Diamondback's presence intriguing is that it could have drastically different impacts on the future of the MCU depending on which version of the character Rosa Salazar is playing. If she is playing Rachel Leighton, Diamondback could be a replacement for Scarlett Johansson's Black Widow as the reformed assassin turned Captain America ally, not to mention a future love interest.

If she is playing Deborah Bertrand, however, then an alliance with Lucia von Bardas could be the first step in bringing Dr. Doom into the MCU. As the Prime Minister of Latveria, Bardas could very well be pulling the strings behind the events in "New World Order," and there could easily be a post-credits scene that shows her hiring Diamondback to go to New York to assassinate Matt Murdock (Charlie Cox).

Another, and maybe more likely scenario, is that she is a combination of the two characters and her history with Bardas and Doom in Latveria is a part of her past, much like Black Widow's history with the Red Room is part of her character background.

Marvel has a history of casting unknowns and up-and-comers to portray characters over a long period of time. People like Chris Evans, Jeremy Renner, Chris Hemsworth, and Tom Hiddleston had careers to stand on but became household names and global superstars thanks to their Marvel characters. Rosa Salazar seems to be a perfect fit and poised to do the same thing in her career thanks to some dynamic performances under her belt.

While Salazar is over a decade older than Scarlett Johansson was when she took on the role of Black Widow (Johansson was 25 when "Iron Man 2" dropped in 2010, and Salazar will be 38 when "New World Order" hits theaters), she has proven herself as one of the most under-the-radar talents in the industry with appearances in the "Divergent" and "Maze Runner" series, "Bird Box," and "Alita: Battle Angel." She could easily play a reformed spy in love with Sam Wilson ... or even one still under the thumb of Dr. Doom and Bardas.

Whether or not she is going to usher in any deeper storylines or set herself up as the new assassin on the Avengers is anyone's guess. But Marvel doesn't often cast names like hers in roles like Diamondback without some kind of plan in place. Her presence could easily lay the groundwork for fans to see the classic "Fantastic Four" villain — maybe even much sooner than we expected.