One of the biggest franchises in the Marvel cinematic universe (MCU) is the "Iron Man" series. The previous trilogy catapulted its main star, Robert Downey Jr. back to the limelight and raised the bar for succeeding MCU movies. However, there have been talks that Downey Jr.'s participation in an "Iron Man" movie ended with the third one.

However, fans will actually see Downey as Tony Stark in an upcoming "Iron Man" installment.

According to Ecumenical News, Shane Black, the director of "Iron Man 3," confirmed that Robert Downey Jr. will be seen in "Iron Man 4." However, although he will still play the enigmatic Tony Stark, the iron mantle that is Iron Man will fall on another character's shoulders entirely. In a report by Movie News Guide, it was mentioned that in the fourth installment, Stark will instead guide Harley Keener in replacing him as Iron Man.

Harley Keener made an appearance in "Iron Man 3," played by child actor Ty Simpkins. In the movie, Keener is also an engineering and machinery tinkerer who helped Tony Stark repair his suit when the latter chanced upon the former's garage after a heated battle with Iron Man's enemies.

Meanwhile, both Keener and Stark's appearances in the fourth installment are also rumored to set the storyline. As suggested by industry observers, the fourth "Iron Man" film could see Keener take on The Ten Rings, a terrorist organization that figured in the "Iron Man" movies, most prominently in the third one. The Ten Rings was behind the Mandarin (played by Ben Kingsley), who was later on unmasked to be only a decoy.

Although still unconfirmed, it is rumored that "Iron Man 4" will be shown sometime in either 2019 or 2020.