The author wanted the mood of the front cover to be gloomy and dark and more on the dramatic side in terms of style.
The story is about twin sisters who have been gifted with supernatural powers and need to protect their town from goblins and vicious gangs. However, she asked for one silhouette so decided to give it more fading effect.
Set in a dark colors illumined by not by some color but flames (the only logical fire source in war, right?).
All elements are joining together to point to and frame the title taking its place in the middle in a very "fatansy-esque" font.