Movies: Dark Phoenix, X-Men: The Last Stand
"“I don’t know how to stop. I don’t know what’s happening to me. When I lose control… things happen, bad things… to people I love.”-Jean Grey"
It was difficult putting Jean Grey on this list. She wasn’t evil in the way viewers look at Donald Pierce or Bolivar Trask. Jean was possessed by a force that made her do things she normally wouldn’t.
In X-Men: The Last Stand, she wasn’t in control of herself and Magneto took advantage of that. Dark Phoenix was similar to when the D’Bari was using her. One could go a step further and say killing Mystique didn’t make her bad either. Nevertheless, that doesn’t mean she isn’t the villain of the two stories.
One of the definitions of a villain is the person or thing responsible for specified trouble, harm, or damage. Jean was all of this. Making Xavier “walk” towards her and not taking responsibility for killing Mystique is what put her on this list. In a lot of ways it’s close to what Wanda Maximoff was like in WandaVision and Doctor Strange: In the Multiverse of Madness. She wasn’t malicious, but the results are the same. She murdered Xavier in X-Men: The Last Stand and almost killed her fellow X-Men as well.
We’re not saying she should have turned herself in to the authorities, but she knew what she did was wrong. Like Magneto said after he came to see her, “You didn’t come here looking for answers. You came here looking for permission.”