Vigor Mortis is a series that goes through exceptionally interesting and gripping concepts and topics, and had me sitting on the edge of my seat all throughout the reading session. Overall, I rate the entire series very highly. But Volume 4 was one that felt like a result of Natalie writing herself into a corner. It felt like she struggled between choosing to either expand the world and narrative with these new ideas, or finally wrap up on the world's storyline and end the series; in the end, she tried to do both, and the end result suffered.
Although I greatly enjoyed the rest of the series, and there certainly are some incredibly heart-tugging moments, Volume 4 is certainly the weakest compared to the prior three volumes. That being said, the entire series is a ride that I highly recommend sitting through for.