'Iron Man 4' release date, plot news & update: Are Robert Downey Jr.'s MCU days numbered?

Can the Marvel Cinematic Universe (MCU) survive without its genius, billionaire, playboy philanthropist? The answer to this question may prove crucial to the fate of a fourth "Iron Man" movie.

Almost a decade has passed since the first "Iron Man" was released in 2008 and introduced to global movie goers the idea of interconnected movies spanning a continuously expanding set of Marvel-based heroes.

Since then a total of 13 installments have been released filling up three phases of the MCU narrative with six movies each, and kicking off the current fourth phase with "Captain America: Civil War."

By latest count, Tony Stark (Robert Downey Jr.) has appeared as a featured role in six out of 13 MCU movies. This tally did not include his cameo in "The Incredible Hulk" and his upcoming appearances in "Spiderman: Homecoming" and "Avengers: Infinity War."

Indeed, the red and gold armored superhero may have become an integral part of the Marvel franchise, but recent rumors have been pointing to his possible death in one of his future movie appearances.

The aforementioned "Spiderman" reboot may reportedly mark RDJ's last MCU appearance, thereby killing off not only the character, but also any possibilities of an "Iron Man 4" movie.

These speculations came at the heels of Iron Man's comic book counterpart reportedly passing the torch to a fifteen-year-old iron-suited superheroine known as Riri or Ironheart. Riri managed to create her very own Iron Man armor prototype using mere scraps she stole from her university.

Another rumor suggested that an "Iron Man 4" may come, if only to serve as a launching point for Riri to finally take up Iron Man's mantle and replace RDJ's $50-million worth character in future MCU line-ups.

Other fans believe that the third Marvel superhero ensemble movie, "Avengers: Infinity War" can better provide a more heroic death for the much beloved superhero who has become the face of the entire MCU franchise.

Meanwhile, a report by CBR.com earlier this year cited RDJ's statement during a "Captain America: Civil War" segment aired on ABC's late-night news program "Nightline." The actor expressed his interest to do one more "Iron Man" movie following his already confirmed appearances on "Spiderman: Homecoming" and "Avengers: Infinity War."

Considering how much "Iron Man 3" grossed in the cinemas, a whopping $1.2 billion, Marvel may just realign its upcoming line-up to make way for a fourth "Iron Man" installment before the fourth phase of MCU ends.

In the worst case scenario, "Iron Man 4" may just end up kicking off the fifth phase of the MCU narrative.

These are all just rumors at this point and Marvel has yet to release an official statement regarding a possible "Iron Man 4" movie.

In the meantime, fans of the iron-suited hero can look forward to his appearances in "Spiderman: Homecoming," which is scheduled for release on July 7, 2017 and the two-part "Avengers: Infinity War" movies releasing on May 4, 2018 and May 3, 2019.