The Case Study of Vanitas/ Vanitas no Shuki (ヴァニタスの手記)
New manga by Mochizuki Jun, the mangaka of Pandora Hearts.
Spoiler for Brief plot summary:
19th century Paris, an alternate universe of steampunk and magic. Young orphan vampire Noe Archiviste is instructed by his mentor to travel to Paris to find and discern the nature of the Book of Vanitas, a clockwork grimoire said to sow curses of madness amongst the vampire race that requires their immediate extermination. However, Noe discovers the book is currently owned by human and self-proclaimed vampire doctor Vanitas, sharing the same name as the legendary Blue Moon Vampire who created the Book to get vengeance on the vampires for shunning him.
Amidst Vanitas's claims he's using the Book to heal vampires to spite the Blue Vampire's orders, the two men find their fates ever more intertwined with each other...