I finished Fablehaven 4 at an ungodly hour this morning.
First, let me say that I have trouble getting into the Fablehaven books every time because they seem to be written by a detail monkey. The descriptions can be very clunky and I tend to glaze over while looking for dialogue. That said, once I got into the meat of the book, things were really heating up.
Although I expected there to be a big secret about Gavin revealed, and I was right about part of the secret, I TOTALLY bombed the secret identity check. I was laboring under the delusion that he was pretty much who he said he was, and just had a big secret. And I liked the darn guy. I was rooting for him and Kendra. I thought we'd find out that he was so darn special because his dad impregnated a female dragon in human form and Gavin was half dragon, himself. WRONG!
I still have my doubts about Warren, though. He has been in a few too many sensitive places at the wrong time, and I am guessing he is a double agent for the Society. I'll probably be wrong about him, too.