: Traditional vampires are born under the Crimson Moon. However, legend speaks of a vampire born under the Blue Moon, also named Vanitas, who created a grimoire to curse all vampirekind in revenge for his ostracization.

: The current human Vanitas uses this same "cursed" book to do the opposite: he heals "curse-bearers," vampires whose "True Names" have been corrupted by a disease called Malnomen, causing them to go into a predatory frenzy.

: The series is framed as a memoir by Noé, who reveals in the first episode that his journey with Vanitas will ultimately end with Noé killing him.