What about alien races? Has Deathbird ever been a hero, and would you count Lilandra (when duties to the empire didn't restrict her) a hero in the classic sense?
Deathbird has aided the X-men, but I still see her as a villain for the most part. Most of Marvel's villains have switched sides at some point or another, if only briefly, to serve their own interests. They rarely make a career out of being heroes, though.
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