Probably a good idea if the idea of slavery in a medieval setting isn/ for you cause further in the story the enemy pillages civillian villages, rapes the women, and captures able bodied men to be slaves while they occupy a fortress. All under the order of the Crown Prince. The story doesn't shy away from the more unsavory parts of medieval settings, esp with how corrupt the enemy kingdom is. This all happens in the 1st volume of the VN btw.