Many fans have thought that the third installment of "Iron Man" in 2013 was the last "Iron Man" film that will star Robert Downey Jr. However, all hope is not yet lost as the New York native gave hints that he'll be back to wear the red metallic suit once again.

During his interview on ABC's Nightline almost three months ago, he mentioned that he is not closing his doors to return to the big screen and play the narcissistic billionaire genius Tony Stark. He even added that he had this feeling that he could do one more.

Moreover, since Marvel Comics has done so many crossover events in the past years involving Iron Man, it's more likely to see Robert Downey Jr. or RDJ in future film projects. A very good example would be the upcoming "Spider-Man: Homecoming" film where he will make an appearance together with Tom Holland who will play the title role and Michael Keaton as the villain Vulture.

Furthermore, RDJ will be in another Marvel movie as Iron Man in the ambitious two-part film "Avengers: Infinity War" where it is said that an ensemble of 67 actors will be in the said motion picture.

With these mentioned future projects of Marvel and Walt Disney Pictures, not to mention a standalone film for the "Black Panther," it is most probable that an "Iron Man 4" movie would be released sometime in the 2020s.

There are numerous villains that Iron Man has faced over the years in the comic series and fans have already made guesses as to who will Tony Stark be facing if a fourth "Iron Man" film would materialize. Fans are suggesting that the Crimson Dynamo can be a formidable foe for the next film, though one of its famous wearers, Anton Vanko, was introduced as Whiplash in "Iron Man 2." Another possible opponent would be Titanium Man, which would also be a good matchup against "Iron Man."

However, the archenemy that's been making quite a buzz right now as "Iron Man's" potential opponent will be the dragon named Fin Fang Foom. With its massive built and with the destruction it can cause in an area, fans would love to see how long would Tony Stark last if he were to battle it out with this green behemoth.