モンスターズ・レイド ～魔に堕ちる姫騎士～

In the distant past, a demon king led monsters in terrorizing the land. Despite efforts by powerful individuals from human, elf, and dragon tribes, they couldn't defeat the demon king but managed to seal its power, bringing temporary peace. The three races then settled in different territories—humans in the plains, elves in the forests, and dragons in the mountains. Many years later, as monsters reappeared and attacks escalated, princess knight Celica, a descendant of the hero who sealed the demon king, led a small army to defend the village of Gazette in the Amusha Plains from a horde of monsters.

[Translated from the official site]