A (usually designed to be sexy) female character who the writer or storyteller goes out of their way to make ridiculously evil so the audience will demand, crave, and celebrate her pain, usually with the intention of having something disturbing or sadistic happen to her.
Friend: Malty was so evil! She deserved what she got in the webcomic!
Me: Of course that torture porn villainess was so evil- how else would the guy who wrote her be able to convince an audience that the woman deserved the sick things he had happen to her? He did it to be an edgelord.