I've bought and read up to 3rd volume, and i'd say she is as the tittle says. It's good so far because the MC isn't a coward and the author doesn't make her weak minded and trying too hard to be a good person like most MC in fantasy manga. The war in this manga actually is dirty and brutal like it should be and doesn't force modern morality on war into the story too much like most modern japanese LN and manga.
I'll rate it 9/10 for realistic view on how dirty war in feudal era.