All of this.She was back and forth on earth during the snap and everyone on earth seems to know the play by play of what transpired during end game so im sure she would be popular after what she did in that fight also.
In Wandavision they all talk about the battle like they watched it on tv like us
But even if this wasn't true, people in real life become stans of random ass artists, celebs, and characters all of the time. Think about all of the people that became stans of fukking Bobo Fett in the OT just because they saw him standing in the cut. Or random mid athletes or rappers that have stans.
Capt Marvel showed up and bodied a spaceship, so it makes sense from that alone she'd have some people on earth watching it on CNN like and would be fans even if she bounced from earth right after.
But just based on how real life works, within the world of the MCU, there would be stanbases for pretty much everyone that showed up to the battle. Cats would be on message boards and twitter getting into flame wars about Mantis and Wong
Last edited: