Shadow of Night by Deborah Harkness
The hero of the story is stunning, broody vampire. The Diana main objective is to locate someone who will help him the all the ways of the witchery. She is the last in the line of the different witches. She never uses her powers. She was blessed with some extraordinary powers. She also broke the laws of the dividing creatures. She also found the all chemical manuscript in Bodleian Library. Now she was bound to Mathew. Diana and Mathew travel back to London. Then vampires come back in the group of the radicals commonly known as School of Night.