Avengers: Endgame - How Captain Marvel Reveals A Key To Defeating Thanos

2. Infinity Stone Signatures

We've already been told that Infinity Stones are only vulnerable to very few things. They're singularities that are powerful on an entirely different spectrum to anything else in the universe: they cannot simply be crushed or thrown into Mount Doom. Destroying them takes a very precise means, as we've been told at least twice in Avengers movies.

In The Avengers, Erik Selvig reveals that an Infinity Stone's power can be counteracted by another Stone. Admittedly at the time, it's wrongly stated that the Sceptre derives its power from the Tesseract, but the logic still works, because it's their shared power source of an Infinity Stone that matters here. He confirms to the Avengers that they can close the portal opened by the cube using the sceptre, offering proof that a single Stone can counteract another Stone.

And then in Avengers: Infinity War, Vision reveals that an Infinity Stone can only be destroyed by something with its own power signature. Given that Scarlet Witch's powers were "turned on" by the Mind Stone during HYDRA's experiments on her, her DNA was fundamentally changed to carry that same signature, allowing her to destroy the source of her powers.

That sequence also shows Scarlet Witch holding off the collected powers of the other five Infinity Stones as she destroys Vision's Stone, suggesting too that a single Stone can withstand the power of all of the others, but cannot destroy them. Both of those points are key to Captain Marvel's place in taking down Thanos, as her new origin means she has the energy signature of the Space Stone. In other words, she could destroy that Stone herself or could counteract the powers of the other Stones (probably not the completed Gauntlet, but at least 5 out of 6 of them at once) or each individually).

In that respect, Danvers is the same as Scarlet Witch, but not only her. There are other characters in the MCU who could reasonably be said to have been marked (and changed) by Infinity Stone signatures. Jane Foster became a vessel for the Aether in Thor: The Dark World; the Guardians channeled the power of the Power Stone in Guardians Of The Galaxy; Doctor Strange wields the Time Stone in an almost symbiotic manner; and it could be said that Gamora being taken into the Soul Stone (as shown at the end of Infinity War) would mark her permanently too.

Could it be that those characters have to combine to take down Thanos? Is that why the writers chose to tie Marvel's powers to an Infinity Stone - so that she was also tied to the rule that individual power cannot compete with the collective?

This all seems to point to something else in Endgame, which helps explain both the need to balance Marvel's power and also circle back on the key theme of unity in numbers over the strength of the individual...