Astrea Record: Dungeon ni Deai wo Motomeru no wa Machigatteiru Darou ka - Eiyuutan

Seven years before a certain boy sets foot in the Labyrinth City, chaos and uncertainty plague the hearts of each god, goddess, and adventurer across every familia. Though Lyu Leon spends her waking hours carrying out the will of the goddess Astrea, she is constantly searching for a brand of justice she can believe in. She may be able to rely on the rest of Astrea Familia to serve as her light in the darkness, but evil yet stirs deep within the shadows. A great conflict draws near, and should it arrive, all of Orario will be shaken to its foundations...!

(Source: Yen Press)