The MCU Still Hasn’t Solved A Big Iron Man 3 Mystery

The Marvel Cinematic Universe has finally moved on from Iron Man and his sacrifice at the end of Avengers: Endgame, but this universe still has one big mystery from Iron Man 3 to solve. Robert Downey Jr’s Iron Man is the hero that kicked off the MCU as it’s known, and as such, he was one of the leaders of this connected universe throughout the Infinity Saga, even leading the original Avengers team alongside Captain America. Iron Man was also the first superhero to get three solo movies in the MCU, setting the model for the rest of this universe’s characters, but his sequels didn’t really match the quality and success of his debut movie.

Iron Man 3 was Tony’s first post-Avengers adventure, and as such, it saw him dealing with anxiety and PTSD as a result of his near-death experience during the Battle of New York. As if that wasn’t enough, Iron Man also had to deal with Aldrich Killian (Guy Pearce), a scientist who created the Extremis virus, through which he recruited a one-of-a-kind type of very dangerous soldiers. At the end of Iron Man 3, Tony, with the help of Rhodey and Pepper, defeated Killian, who was later killed by Pepper, and they all moved on. However, Iron Man 3 didn’t explain what happened to Extremis after Killian’s death, and it has forgotten about it ever since.

Related: Iron Man 3’s Extremis Could Be The Key To Eternal Life

Iron Man 3 Didn’t Give Closure To Extremis

Extremis is an advanced form of genetic manipulation created by Maya Hansen in 1999, who showed it to Tony Stark while she tested it on plants, with Stark providing additional help through a formula that would help reduce the treatment’s volatility. Extremis went through a major upgrade years later thanks to Killian’s Advanced Idea Mechanics (A.I.M), which provided additional funding for the treatment to begin experimental testing on human subjects, recruiting amputees and other disabled people. These subjects were cured, and Killian convinced them to work for A.I.M. as assassins and soldiers. Aside from healing wounds and regenerating body parts, Extremis granted its subjects enhanced physical performance, and superhuman strength and reflexes, as well as generating extreme amounts of heat, which trained subjects could focus and conduct through a single area of their bodies.

Extremis was the reason why every enemy Iron Man came across in Iron Man 3 was so difficult to defeat and overpower, so this virus had a main role in the movie, yet it didn’t get the closure it needed and deserved. Hansen was killed by Killian and the latter was killed at the end of Iron Man 3, but the Extremis virus didn’t die with them, and as not all the Extremis soldiers were killed or cured, Iron Man 3 left a major loose end that the MCU has chosen to ignore since the movie was released.

What Happened To Extremis After Iron Man 3?

As mentioned above, not all Extremis soldiers were killed at the end of Iron Man 3, and this was confirmed in Shang-Chi and the Legend of the Ten Rings. When Shang-Chi arrives at the Golden Daggers Club in Macau, different fighters are shown, among them one who is an Extremis user. Prior to the events of Shang-Chi, the in-world book The Wakanda Files: A Technological Exploration of the Avengers and Beyond revealed that, following the Battle on the Norco at the end of Iron Man 3, Shuri started investigating Hansen’s Extremis research, growing fascinated at the concept and how it successfully enables regrowth of lost body parts, and even though it has deadly side effects, she concluded that it has potential. Extremis could still be of great use in the MCU if it’s in the right hands, and with geniuses like Shuri and Bruce Banner still active, Marvel is wasting this one-of-a-kind treatment. Although a lot of time has passed since the release of Iron Man 3, the MCU can still solve its Extremis mysteries through Shuri and other characters.