That is true, at his worst Thanos is pure evil but there have been many occasions where he has fought for the greater good of the universe.
Carnage is pure insanity, and a serial killer. Most guys like that have no conscious or regret for any harm they have done, and I don't ever recall Carnage doing a good deed.
Maestro comes to mind as well, he has no concern for anyone but himself and has killed all challengers to his rule. He endangers the innocent, and most often he does what he does just to get a little fun out of life.
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Sig by Quincy, the Dark Knight of Signatures!
Mephisto IS the most evil. If only because everything he does, is somehow tied to his WANTING to indulge in evil. He may not always be the most powerful evil being around, but there is no other villain in Marvel that promote evil for it's own sake, more than Mephisto, IMO.
Gender: Male Location: Killing Kakarot in Chicago,Illinois
Imo Marvel has no greatest evil because all their characters have showed some sort of compasion, even Mephisto has children. Carnage has liked someone(for a little bit) and so has Thanos, Doom, Kingpin, some are just wanting power or revenge. I'm sure there must be someone who is truly evil in marvel but right now I can not think of any.
"Llan is one of the most ancient of evils and said to be the most powerful. He is the architect of madness, the bringer of despair and he's the opener of the way for all evil that lurks outside. Llan was also said that he is the next worse thing to the devil himself and Llan isn't a demon or a god, something far worse."