Marvel’s Phase 4 could have paid off one of the last biggest Iron Man mysteries. However, the perfect opportunity was ultimately missed with 2021’s Shang-Chi and the Legend of the Ten Rings. Introducing Shang-Chi as a martial arts hero and the son of the true Mandarin in the MCU, Shang-Chi could have addressed enduring question marks that have persisted ever since 2013’s Iron Man 3.

As seen in the third Iron Man movie, Aldrich Killian and his think tank Advanced Idea Mechanics (AIM) co-opted the Ten Rings and Mandarin names to orchestrate complete control over the war on terror. This was also done through their creation of Extremis, a volatile nanotechnology that could repair limbs and strengthen the body but also risked exothermic explosions due to overheating. To that end, the return of the real Ten Rings and Mandarin in Shang-Chi could have been the perfect means of following up on Extremis and its fate which Iron Man 3 neglected to answer.

Shang-Chi Could’ve Had The Perfect Extremis Payoff But Missed It

Extremis Was Featured In The Movie

In Iron Man 3, Killian had an actor named Trevor Slattery play the role of the Mandarin, a public face to instill fear with Killian also intending to have control over the President of the United States once President Ellis was killed and the Vice President took over (who was in AIM’s pocket). However, it was eventually revealed that the real Mandarin did exist in the MCU, one who was none too pleased that his name had been used as confirmed in the one-shot All Hail the King and later on in 2021’s Shang-Chi.

While Shang-Chi did address Sir Ben Kingsley’s Trevor who had a role in the film and had been the Mandarin’s prisoner, the film also had the chance to address what happened with Extremis, but ultimately didn’t. In the wake of Iron Man 3, very little was done with Extremis aside from some brief references and involvement in ABC’s Agents of SHIELD. However, Shang-Chi did feature someone with Extremis in their system who makes a brief cameo just before Wong fights the Abomination. While this confirms Extremis was still floating around seedier parts of the MCU, the nanotech was never directly addressed.

Why MCU’s Shang-Chi Needed To Miss Out On An Iron Man 3 Follow-Up

A More Magic-Focused Story (And Already Had Trevor)

Ultimately, it makes sense why Extremis didn’t play more of a role in Shang-Chi and the Legend of the Ten Rings. After all, Trevor was already featured in the movie as the follow-up connection to Iron Man 3 with its Mandarin and Ten Rings ties. Furthermore, Shang-Chi has a very strong magic focus with the actual Ten Rings the crime syndicate is named after, along with the mystical realm of Ta Lo. As such, a more science-flavored tangent with Extremis would likely have felt out of place beyond the small cameo that was made.

MCU’s Actual Extremis Answer Was Way More Confusing

Secret Invasion Had Extremis

That being said, it’s rather unfortunate that Extremis’ true return in the MCU was so confusing in 2023’s Secret Invasion series. Extremis was included in the DNA samples and subsequent powers retrieved by Gravik to turn himself and his followers into Super-Skrulls. However, nothing was revealed about what had happened to the nanotech over the years nor why it didn’t seem to cause any of the previous side effects or combustion issues as had been seen in the past.

Extremis suddenly being so stable could perhaps be attributed to Skrull genetics allowing for better regulation of body temperature. That said, it was never confirmed either way. Seeing as how the Mandarin of the original comics had ties to Extremis on the page, it certainly would have been nice if similar connections had been established in Shang-Chi after Iron Man 3 failed to provide adequate closure for the fascinating MCU nanotech.