I love Greek mythology, and one of the most interesting myths to me is the myth of the harpy. Depicted as either beautiful or ugly, depending on what you read, harpies are best known for being thieves, often of food, and violent to boot. I wanted to make a new twist on a classic myth, and I think steampunk suits the modern harpy quite well.
Fun fact: she is not flat-chested, per se, seeing as she doesn't have breasts. She's a bird-woman, and birds don't lactate. The bump on her chest is actually an enlarged sternum similar to that of birds that gives her flight muscles something to attach to.