What is Extremis in the Marvel Cinematic Universe?

Had the second episode of Secret Invasion thrown any more developments at us, the world would no doubt have faced a neuron shortage like no other; as the miniseries continues to replace old questions with a myriad of new ones and ramp up the volatility of the stakes, we’re watching eagerly as the MCU‘s foray into political thriller territory unfolds with increasing delectability.

But that’s not to say that echoes of usual Marvel antics aren’t in play, either; indeed, following her participation in the attack on Russia, G’iah stumbled upon a DNA collider hidden in Gravik’s base, and while its presence does no favors for the otherwise grounded nature of the show, it nevertheless sets a rather terrifying precedent for the state of affairs ahead.

In their hunt for suitable entities to merge their DNA with, the in-the-know Skrulls have rounded up the likes of Frost Beasts, Cull Obsidian, and Groot, as well as the bioelectrical virus Extremis, which could end up being the key ingredient in this daunting recipe. But what exactly is Extremis?

What is Extremis?

Extremis is a nanotech-enabled virus created by genetic biologist Maya Hansen, who was later enlisted by Aldrich Killian to perfect its stability under the eye of his A.I.M. agency. The virus enhances the subject’s DNA, specifically targeting the brain’s bodily repair functions and subsequently allowing the subjects to heal from most all wounds, and even regrow lost limbs and body parts. Some users are even able to manipulate the metabolic nature of the virus’ repairing ability to generate dangerous amounts of heat, which can lead to the creation of explosions if channeled properly.

Killian intended to use the virus to create an army of Extremis Soldiers, who were later wiped out by Iron Man, War Machine, and J.A.R.V.I.S. in Iron Man 3 after Maya witnessed the horrors of Extremis experimentation behind A.I.M.’s doors and turned to Tony Stark for help. The virus was later acquired by HYDRA’s Centipede Project, where it was combined with Gamma Radiation, Chitauri technology, and a type of Super Soldier Serum to create their own breed of enhanced soldiers. Thanks to the efforts of Nick Fury, Phil Coulson, and the latter’s team of S.H.I.E.L.D. agents, the Centipede Project has since been extinguished.

It’s no surprise that Gravik wishes to arm his Skrull warriors with the gifts of Extremis, then; having elite alien soldiers on your side is one thing, but elite alien soldiers that can cause explosions with their bare hands whilst being unfairly difficult to kill? Well, we can only hope that Fury manages to foil Gravik’s plans before it comes to that.