Kaketa Tsuki no Mercedes: Kyuuketsuki no Kizoku ni Tensei Shita kedo Suteraresou nanode Dungeon wo Seiha Suru

Mercedes, born into vampire nobility in the vampire nation of Orcus, carries the memories of her previous life — a mundane, unfulfilling human existence that ended in an unremarkable death. Despite her noble birth, she and her mother (one of several concubines in the household) live in poverty, always at risk of being cast aside. Determined to escape that precarious life and find real purpose this time around, she becomes a "Seeker" — a dungeon explorer role open to anyone regardless of age or gender — and heads into the dungeons alone. Solo exploration proves brutal, but she starts subduing the monsters that attack her (a giant, a black wolf, and others) through sheer strength and taking them on as companions instead of enemies. With her growing group of monster allies, she sets her sights on conquering the dungeon entirely, driven by a vow to the moon and a refusal to turn back no matter what she finds in its depths.