The iDOLM@STER Shiny Colors

Scorned by others of his kind for being born under a blue moon, the vampire Vanitas grew afraid and desolate. According to legend, he created a cursed grimoire known as the "Book of Vanitas," and it is said he would one day use it to bring retribution upon all vampires of the crimson moon. In 19th century Paris, Noé Archiviste is searching for the fabled Book of Vanitas. Whilst traveling aboard an airship, he is saved from a vampire attack by an eccentric doctor who calls himself Vanitas and carries the very tome he seeks. Ironically, the self-proclaimed vampire specialist is a mere human who inherited both his name and the book from his master, the same Vanitas of legend. As the odd case of the Charlatan's Parade crops up, the doctor's ability to restore sanity to vampires by recovering their true name will prove most beneficial. [Written by MAL Rewrite]

Fourth season of Strike the Blood.

Once, vampires and humans lived in harmony. Now, a young girl and a vampire queen will search for that Paradise once again. In the divided world of the future, two girls want to do the forbidden: the human wants to play the violin, and the vampire wants to see a wider world. (Source: Netflix, edited)

The OVA will be focus on when Kujaku Nijou first entering group, which occurs one year before the main anime begins.