This is awesome. I like the use of greyscale so that you really pay attention to the design and anatomy instead of being overwhelmed by color. I also like the varied line weight through the figures and the use of white as a highlight instead of a base tone.
The poses are nice and strong for the two figures. Many female characters are drawn unbalanced to show off their feminine allure, regardless of the kind of person they are. I'm glad that you chose something that showed confidence and that she's a soldier who is not to be trifled with.