Source: comicvine.gamespot.com

6. Madame Masque

Look, her real name is Giuletta Kristina Nefaria. But I’m gonna call her by her alias, Whitney Frost, because it’s the name she usually goes by, and because it’s one hell of a lot easier to spell.

When Frost discovered that she was actually the daughter of Avengers villain Count Nefaria, she went to work as leader of the Maggia. During that time, she suffered a tragedy and had her face horribly scarred, leading her to her identity as Madame Masque. Under an assumed identity, she wound up falling in love with Tony Stark, and the two would flirt on and off for the remainder of their careers.

She also died and cloned herself a bunch and then came back and then the clones died and it was a whole thing that we are just skipping right over.  The Hood used her as a weapon against the Avengers. At this point, she and The Hood became constantly intertwined. She fought Hawkeye and Moon Knight and Hawkeye (the other one) and Iron Man again, until she eventually got possessed by demons, and Doctor Strange had to cure her.

And that was the last we saw of her.