Diary of a demon. Life is a Story - story.one

Diary of a demon is exactly as stated, a diary. The diary of Caiden, a vampire-like creature known for a count of at least 100 murders in his own country, and many more all over the world.
This diary shows just a few entires he wrote about his wife, her end, her murderes ends, his biggest, as well as his own newest murder. Who might that be, dearest reader?