Mario was the villain in Donkey Kong Jr. Kept DK locked in a cage, whipping him, while sending monsters to murder DK's kid.
I'd say (in the case of long-running characters) they should have spent the majority of their time as a villain. While Mario was evil there, clearly, that's nothing compared to how often he was a hero. Comic characters can be harder, but...eh.
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In this world which will someday fall to ruin...
...dreams and hopes don't matter at all.