The girl is standing in front of the monster. She is dressed in a green cloak with sleeves, without a hood, and holding a bone whip with joints in her hands. 
The monster in front of her looks like a lycanthrope, its fur is black with red markings. 
They are not aggressive, they just are looking at each other.
Background: catacombs, dark, but they stand in a spot of natural light falling from above