Suggested by Jean Thor is a powerful fighter from Marvel and you could easily make the case that he is one of the strongest Marvel characters out there. He has a lot of strength and speed but this will not be enough to stop Majin Buu. Buu was able to hold his own against Goku for a time and has also gotten many extra power ups in other DBZ video games. His speed and power are just at an absolute crazy level so it’s hard to see Thor being able to match him blow for blow. Buu wins.
The nine worlds will shake with fear, along with the Marvel Universe, if Buu eats Odinson. Mjolnir will be Jane’s, that is for certain.
Agreed, nobody will want to mess with Buu at that point, his power will surpass all limits