The reader was exposed to both characters, Jack Gregory (the Ripper) and Janet Price, in the Rho Agenda books. Based on the Publisher's Marketing Promo, we are led to believe that this book (Once Dead) would develop the supernatural element of Jack Gregory. True to the promo, Jack is possessed. However, I agree with previous reviewers, the supernatural aspect of Jack's personality never gets any traction. The reader is left to our own inventions and imagination too much.
The genre is a spy thriller integrated with a supernatural theme mixed with a developing relationship/partnership between the two protagonists. This theme is similar to those encountered by either Mitch Rapp or Scot Harvath. What starts out as a relatively straight forward protection contract embroils Jack into a major terror plot against the USA. Jack is ostracized by all the USA spy agencies except for the NSA. To find out why, the NSA sends one of its lead assets into the picture, i.e., Janet Price. Their relationship and/or partnership is well developed and the reader shouldn't have any trouble following along. However, the story gets more complicated with the introduction of the remaining characters. I think the author handles it well but it can be a little confusing for the reader; i.e., how and why did we get from point A to B?
Hopefully, future books will develop the supernatural aspect of Jack's personality. I will read future books just to see if Jack's internal conflict is resolved. I recommend this book just for the development of Jack and Janet's partnership.