'Iron Man 4' cast news, rumors: Robert Downey Jr. may be replaced after Tony Stark's successor is named

Riri Williams, the new Iron ManMarvel Comics

Robert Downey Jr.'s return for the fourth installment of the "Iron Man" movie franchise remains uncertain after Marvel dropped the news about Tony Stark's replacement in the comic book series in July.

Express UK revealed that the billionaire playboy who owns Stark Industries will have to retire his Iron Man suit at the end of the Civil War II arc. But Iron Man will not be gone for long, since he will be replaced by a 15-year-old black girl named Riri.

According to reports, Stark's replacement is a science genius who is enrolled at the MIT. She reportedly built her own Iron Man suit that impressed the Stark Industries CEO. However, Riri will not use the Iron Man monicker, since she will refer to herself as the Ironheart.

The "Invincible Iron Man" series writer Brian Michael Bendis explained the reason why Riri chose that name instead of the other rumored aliases.

"Iron Woman seemed old fashioned to some. Iron Maiden looked like a legal nightmare," Bendis said in the report. "And Ironheart, coined by [former Marvel Entertainment Chief Creative Officer] Joe Quesada, after I told him my planned story for Riri, speaks not only to the soul of the character but to the Iron Man franchise as a whole."

However, Marvel has yet to clarify what will happen to the film franchise after Riri's introduction in the comic series. According to reports, Downey Jr.'s contract with the film studio only requires him to portray the role until the fourth installment of the "Avengers" franchise, which is expected to be released in 2019. He already revealed that he is willing to return for a fourth "Iron Man" movie.

If Marvel Comics will feature a new Iron Man, it could also mean that the film version of the franchise will also be ready to begin with a female version of the character.