is a Japanese light novel series written by Firehead and illustrated by KeG. The series was originally serialized on the online service Shà Âsetsuka ni Narà  from October 2018 to November 2022, before TO Books acquired it for publication beginning in May 2021. Four volumes have been released as of August 2025. A manga adaptation illustrated by Pochi Edoya began serialization on TO Books's Comic Corona website in August 2021, and has been compiled into five volumes as of August 2025. An anime adaptation has been announced.
The series follows Mercedes Grunewald, a vampire woman and the reincarnation of a Japanese person who died in a past life with regrets. She lives in the countryside with her mother, who was forced away by her father after a falling out. Although of noble descendent, she is left out of his line of succession due to being born to a concubine. With an unclear future, she decides to become a dungeon crawler to gain strength and wealth.
The series is written by Firehead, who originally posted it as a web novel on the online service Shà Âsetsuka ni Narà  from October 1, 2018, to November 6, 2022. It was later acquired for publication by TO Books, which began publishing it as a light novel on May 10, 2021. Four volumes have released as of August 2025. The series is licensed in English by J-Novel Club.
A manga adaptation illustrated by Pochi Edoya began serialization on TO Books's Comic Corona website on August 23, 2021. The first volume was released on December 15, 2021; five volumes have been released as of August 2025. The manga adaptation is also licensed in English by J-Novel Club.
An anime adaptation was announced on August 7, 2025.
By August 2025, the series had over 150,000 copies in circulation.