Thanos’ Headbutt No Effect on Captain Marvel:
Captain Marvel is arguably the strongest hero of the MCU. She along with Scarlet Witch are really the overpowered ones and that’s mainly because of the origin of their abilities. Both Scarlet Witch & Captain Marvel were humans who got abilities from the Infinity Stones. And that’s why they were probably the only two heroes who almost took Thanos down if it wasn’t for his cheating reversals. Captain Marvel managed to establish the fact that she is much stronger than Thanos. But we’ve got a theory that might actually answer how Thanos felt so inferior against Captain Marvel.
With 6 Infinity Stones at his disposal, Thanos was unbeatable in Infinity War. Thor almost took him down, but still Thanos managed to fulfill his goal. In Endgame, he came without the stones. All he brought in was his sword, his strength and battle experience. And he still was tough for the big three Avengers to take down. Iron Man, Captain America & Thor together could not defeat Thanos. Cap came close but he was surely underpowered. Scarlet Witch also came close & so did Captain Marvel.
While Scarlet Witch has strong abilities, she doesn’t have indestructible superhuman strength. If Thanos would’ve laid one hand on her, she would’ve suffered an even worse death than her lover or her brother. That isn’t the case for Captain Marvel. She was so strong that Thanos tried to surprise her with a head butt and she didn’t even blink. It was a Batman V Superman moment where Batsy punched Superman and he didn’t even move. Only this time, Batman was Thanos, a powerless man wearing his broken armor, & Captain Marvel was Superman, the omnipotent hero raised on Earth. That little head butt right there proved that Captain Marvel is much stronger than Thor. Thanos wiped the floor with Thor, but to take push Captain Marvel away, he needed some external help.
CBR presents a theory that tells us how Captain Marvel seemed so insanely powerful. As we know, her powers originate from the Space Stone. That’s why she could turn into a super saiyan, shoot energy blasts and fly faster than a tracer bullet. And this power from the Infinity Stones is probably what gave Captain Marvel an extra energy boost when she was trying to stop Thanos from closing his fist. Apparently, she instantly connected to the raw power of 6 Infinity Stones as she held Thanos’ hand. She started to draw even more power than Thanos could imagine, and that’s why the headbutt from the Mad Titan had absolutely no effect.
You could parallel it with Cyborg in Justice League. Since Cyborg’s powers are from a motherbox, he was able to establish a connection with the mother boxes when they formed the Unity. In theory he could actually draw more power from the Unity and that’s what happened when all the Infinity Stones were together. Captain Marvel absorbed power from it. But when Thanos took the power stone out, he broke the connection of Carol’s power absorption and she instantly became vulnerable while Thanos grew “power”ful.
This could work in theory, and with this analogy, even Scarlet Witch might be able to draw more power from the Infinity Gauntlet. Furthermore, this theory could be used to depower Captain Marvel in her second film. Because of her strength, the third act of Captain Marvel almost had no stakes in it. She wasn’t vulnerable and Yon Rogg was no match for her. Their last encounter turned in a good laugh in the theatres, but it wasn’t memorable at all. To raise the stakes and make Carol a bit relatable to us humans, Captain Marvel 2 will have to either bring a villain stronger than Carol or depower Captain Marvel.
Giving us the explanation that Captain Marvel was drawing power from the Infinity Gauntlet, and she got a little weaker as Thanos struck her with the Power Stone could work in depowering her, or presenting a stronger villain. We know that this theory is most likely to be shot down because Carol is as strong as she was shown, but still it’s a good explanation to why Captain Marvel suddenly had God level powers that exceeded even the God of Thunder.