One of the too-often used tropes these days is to make Superman into a violent and evil character. Besides fundamentally misunderstanding what the character is about, it is far too easy. Turning the proverbial god on earth into a violent despot takes no imagination. There are so many other characters whose powers seem more subtle but they are significantly more deadly.
If the powers of some superheroes are examined analytically and scientifically, there are many superhero powers that can be used in deadly and even horrific ways. They can maim, injure and even kill people in new and unique ways that would make the carnage-created antiheroes like Wolverine or Deadpool or assassins like Deathstroke look like the work of amateurs.
It is only the heroic nature, moral compass, and general desire to do good that keeps these heroes from following these dark paths. Strip that away and you have characters that could become the most heinous villains the comics have ever seen. Or, at the very least, characters that would have a hard time looking at themselves in the mirror and still calling themselves heroes.
10. Emma Frost
Emma Frost is an Omega-level telepath with an incredible number of mental abilities. She is a stronger telepath than Professor Charles Xavier and while she is on Krakoa’s Quiet Council and has been an X-Man in the past, she is definitely morally dubious at best. Nothing is more important to Frost than her own life and comfort and she will go to great lengths to ensure those aspects are strong.
Emma Frost can attack the minds of people in both passive and somewhat gentle ways and more direct and violent ones. Emma has the ability to mentally “sedate” someone, rendering them unconscious and keeping them that way until she chooses to revive them. She can also cause someone to have total amnesia, simply emptying their mind. Conversely, Frost can fill a person’s mind with vast amounts of information, incapacitating them with knowledge.
The White Queen can take mental control over anyone’s mind and body, forcing them to do what she wants, She can also induce intense pain in someone with a thought. Emma can induce temporary paralysis in someone's mind or body, as well. She can also produce psionic lightning and psionic blasts. Even without her mental abilities, Frost's diamond form is super strong and she could literally slice someone to death with her diamond fingers.