The fifth chapter of Witch Hunter is called "Lapsus Angelus". In it, we go back into the distant past of Sevenpeaks to find out where the evil of the Black Sickle originated...
The entire Witch Hunter story is available on tape with lots of extras (it's not really a tape but a USB flash drive that looks like a tape).You can get it as a download (also with a lot of extras) and even as a novel (both in print and as an e-book).
PS: just type in "Witch Hunter Domien" on your Amazon of choice (.com,.co.uk, .de, .ca or .fr) to find the book, like this: