The World's Strongest Rearguard: Labyrinth Country's Novice Seeker, Vol. 7 (light novel‪)‬

Arihito and his party faced off against the Shining Simian Lord in District Five and successfully rescued Elitia, but the curse this horrible beast inflicted on Theresia is destroying her bit by bit. If nothing is done, she’ll soon become another one of the Simian Lord’s mindless underlings. In order to save his companion from this dreadful fate, Arihito must find a way to lift the curse on her and defeat the Simian Lord... But can Theresia hang on that long...?