The character's name is Monster.

Basically I'm wanting to play with the idea of social separation. A friend of mine was disfellowshipped from my religion, which means until she is allowed back in none of her friends who are Jehovah's Witnesses (of which I'm one) are to speak to her, even to the point of not greeting her. That level of social ostracism is a part of the creation of the character.
She is beautiful/normal looking but if someone looks at her full face they have a paralyzing, traumatic experience. The (unexplained) effect if to hit them with the weight of every morally wrong decision they've ever made all at once, overloading their conscience and their minds.
The only explanation as to how this happens is vague, tied into something that happened to her and/or that she did. Sometimes the comment is made of someone who is having to endure either extreme shame or guilt "How could they show their face?" That is her, that is why she is called Monster.
Further, the idea is that this is somehow imposed, not something coming from her own power. Likewise she cannot be killed but can be hurt (easy escape is not allowed, not even death) So her journey, her arc is one of redemption from the unforgivable. It boils down to a play on Medusa, the woman who could turn men to stone with just a look, this time she is the main character, the hero of the story, if you can use that word)
The costume is a simple mask with an "M" on it, along with normal clothes. She has money but isn't one of the super rich. Her character is a realist, an enforced pessimist and someone who is sharp tongued with idiots. She's obviously not a popular person, most people move to the other side of the room when she walks in. Her power is a nuclear option. It's room clearing and absolute but also one she hates.
I keep thinking there's something missing, like there's an aspect she's missing that would make her jump out as a character. The truth is that good stories make good characters but I keep feeling like there's on small piece she still needs.