I'm a Behemoth, an S-Ranked Monster, but Mistaken for a Cat, I Live as an Elf Girl's Pet, Vol. 10 (manga)

An urgent message arrives for Aria and her friends—Vasargo of the Four Fiends is trying to obtain the Philosopher’s Stone, and he’s appeared with his troops in Aria’s hometown. With her companions in tow, Aria rushes back to the village and reunites with her mother, Leona. Together with Leona, now a captain of the Amazoness Corps, the group braces itself for the enemy’s attacks. It’s finally time for the decisive battle!