Evelynn is usually a purple demon lady who runs amok in a shadow form, out of sight of enemies, and then pops out of nowhere to assassinate them. Her lore is centered around being a succubus. That being said, her K/DA counterpart is a diva, and her romantic partners tend to go missing. Her real-life counterpart is Madison Beer, an American singer who has 11 million Instagram followers.

From https://www.polygon.com