Memoir of Vanitas

Story:

Late 19th century in Paris. Human Vanitas works as a physician for vampires and aspires to save them. He breaks a terrible curse that corrupts vampires and transforms them into blood-sucking monsters with a magical book called The Vanitas Grimoire. But, it is said that this particular book is a cursed text that gives rise to vampires on nights when the blue moon is full. Vampire Noe is looking for The Grimoire. Who is Dr. Vanitas, really? What secrets does he possess, and what do they portend for the vampire species?