Thanos. He's just too powerful, versatile, and durable. Compare and contrast how each character in this thread took a hit from Mjolnir. Thanos shrugged it off, MS got it's teeth broke.
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..even the outer hells are indifferent matters for they bow only to potent and archaic Nodens.
Very original matchup,zopzop petty much said it all here.but I would like to add when thor took on the midgard serpent he was wearing an armor just to hold his body together he had been cursed by Hela with being unable to die.So when they do the big time collision Thor avoids the prophecy of death and T.M.S crashes in a smoking heap.Thor is like living jelly in his armer at this point.at any rate thanos takes thor even when he had the power gem,so the serpant goes down it` not the easiest win for Thanos but he gets the W over the serpant.