Well, Thanos being amped to such an absurd degree vs. Mxy isn't as spite-y as Thanos under his own power w/o prep or plot device artifacts versus Fury or MoD.
Because , Mxy , from World's Funniest , probably has one of the greatest feats ever written in comicdom .
I personally believe that Thanos could win this , however , looking at their respective power-levels and feats , its debatable .
They both destroy the omniverse, and are left with each other alone in nothingness.
I guess it's depends on who's got more stamina and and last "longer", though I mean if they destroy the concept of time, then there's really no end to the battle.
Thanos did not destroy everything, I believe he only destroyed half of the 616 verse, and to bring it back he had to die.
Where as Mxy destroyed the DC Omniverse, from alternate to Elseworld, he destroyed all of it. Even better, is the that he just snap his fingers and everything came back, he then went on to tell Bat-Mite same time next week. It's implied that Mxy destroys the Omniverse on a regular basis.
Gender: Male Location: The Fortress of Solitude in Venus
Is hard to say.
But based on panel evidence I have to go with Myx and his WF.
He does this and He is just playing around, the other guy is serious about it. So it seems Myx does this casually and with out even paying attention to it.
Basically he destroys the omniverse as a side effect of him playing
Gender: Male Location: somewhere within time & space
"Thanos only destroyed half the 616 reality" in The End: Marvel?
Was there a mini retconned extra-tie in I missed?
That aside, destroying/rebuilding reality is moot sometimes.
The LT fashioned the power of Two MegaverseS (each a collection of Multiversal power) in one hand
on his other hand, he spins the wheel of destiny concerning the Alpha & Omega.
Yet, as monstrous as the LT may be in comparison with territories like UniverseS, or even MultiverseS,
he was still absorbed like a mote in a storm by THOTI,
BEFORE THOTI even absorbed 616 let-alone the rest of space-time.