The TV series is adapted from an original South Korean webtoon series with the same title, Seoul Vampire, which is currently ongoing on Naver Webtoon.
The original story takes place in the 18th century of the Joseon Dynasty, the time when Catholicism began to spread on the Korean Peninsula. Western missionaries clandestinely entered Joseon, and among them was a vampire disguised as a missionary. During this era, the Korean Peninsula was characterized by a hierarchical society, with approximately half of the population being slaves. Through Catholicism, both slaves and low class sought a vision of salvation, equality, and freedom that had been previously elusive. Conversely, scholars were intrigued by Western knowledge and culture. A Vampire alchemist who came to the Korean Peninsula to create a new species, a man from the Netherlands sought to reclaim his lost life, and a boy and a girl aspired to find happiness in a world where everyone is equal beyond love, as soulmates. Seoul Vampire is a fantasy romance genre that combines the captivating plot and spectacular action by harmonizing Western vampire culture with the historical background and culture of Korea.