The Magic in this Other World is Too Far Behind! (Manga) Volume 4 by Gamei Hitsuji

Suimei and Lefille continue on their journey together towards the Empire, but stumbling across a grievously wounded survivor from a second attack on the trade corps sends Lefille running in the other direction. Suimei chases after her, but knows what lies in store. As it turns out, their encounter with the demon army isn’t over—in fact, it’s only just getting started. Can Lefille confront her dark past and take down Rajas? Or will fighting her own demons prove to be too much?