I don't write a lot of reviews because I find that I'm not really very good at them, but I saw that this book was not getting a lot of feedback, and what it was getting was pretty negative, and I feel like I have to defend it. (Without spoiling the book for others, like some of the other reviewers. Tsk.)
Let's start by saying that if you read Havemercy, you know these two authors are capable of incredible writing. And Dragon Soul does not disappoint in that category. The writing is very well executed. It's not unbelievably fantastic, but it's well done- I didn't have any spots where I got tripped up or confused. The authors' point always comes across clearly. Another reviewer remarked that a particular phrase was being repeated too many times- I watched for a phrase throughout the book (I forgot exactly what it was) and I didn't find anything like that. Then I came back to Amazon and saw which phrase the reviewer had mentioned, and I went back through the book, and it still didn't strike me as out of place.
I also felt that the characters were well realized. I love the way Rook is written, because when you're reading him in first person, you feel like maybe he's misunderstood, etc., but then when you read Thom talking about Rook, you realize that that's just his character, the way he his. It's a great example of an author showing instead of telling, because you do actually fall under that spell. I felt that Thom, Rook, and Madoka were interesting, fully thought-out characters. I loved each of their story lines and never felt bored when I was reading them. I think the authors may have slacked off a little with Malahide. She doesn't remind me of Caius, but I did feel she was a little less... real, I guess is the word I'm looking for. She was interesting, but I felt that I didn't care as much what happened to her. However, I'm hoping to see her character expanded in future books.
This book is lively, fast-paced, and it made me laugh quite a few times. It is not, though, perfect, and does have a couple of flaws. If you read Shadow Magic before this, you'll understand when I say that the biggest flaw I found was that, throughout the whole book, the authors seem to be leading up to certain characters becoming romantically involved. But at the end of the book, you find this doesn't really pan out the way you thought it would. Perhaps these romantic interests will be progressed upon in future books? I hope so.
And I do hope these women will continue to write, because they really are talented. Havemercy was one of the better books I've read in a long time, and while Dragon Soul is not quite as good, it's still very entertaining, and very worth reading. Give it a try.