Originally posted by FrothByte
Thor. Why? Because kryptonite.With kryptonite even an old lady can render Superman helpless whereas there's no other way to beat Thor than an all-out fight. There's also the fact that Thor is king of a whole other world and can probably instigate an invasion.
Thor also doesn't have any real ties to Earth, not as strongly as Superman does anyway. You could always just threaten Martha Kent to keep Superman in line.
And as fast as Superman is, he doesn't have Thor's teleportation powers. When you combine that with Thor's city-busting attacks then he can literally destroy multiple cities in only a few seconds.
Kryptonite isn't standard knowledge though, and given this is a bloodlusted Superman looking to slaughter the innocents of the world ala the Plutonian he will go for the ones who know of it and could use it to threaten him first, aka Bruce Wayne (Clark knows Bruce is Batman right? I honestly don't remember...), Lex Luthor, and their affiliates. Even with kryptonite, as Superman said, if he wanted it Bruce would have been dead already.
As far as Thor being the king of a whole world, the Asgardians are essentially decimated as of Infinity War, and all of them combined are still frankly irrelevant compared to the lethality Thor and Superman can bring.
Also, Thor didn't destroy Sokovia by just hulking out and smashing the city, and I don't know how anyone thinks as much.
FRIDAY: The anti-gravs are rigged to flip. Touch them, they'll go full reverse thrust. The city's not coming down slow.
STARK : Spire is vibranium. If I get Thor to hit it...
FRIDAY : It will crack. That's not enough. The impact would still be devastating.
STARK: Maybe if we can cap the other end. Keep the atomic action doubling back.
FRIDAY: That could vaporize the city & everyone on it..
STARK : I got it. Create a heat seal. I could supercharge the spire from below.
FRIDAY Running numbers
FRIDAY : A heat seal could work with enough power.
STARK: Thor, I got a plan.
We literally see earlier in the film that Thor uses Mjolnir strikes on Cap's shield to amplify his attacks.
It is a shared feat relying a reaction with the vibranium Thor struck.
If Thor could have just destroyed the section of Sokovia outright he would have.
But anyway, neither would really be stoppable. Both can go from one end of the globe to the other before any response could be made, so the Earth is doomed in either case.