It's hard to rate this book. On one hand it has a really good concept going for it but on the other hand the writing is stilted and telegraph like at times. There are plenty paragraph in the book where sentences are started over and over again like this, "I did..." "I saw..." "I felt.." or "He said..." "He grabbed..." "He looked..." it read very amateurish and like the book never did pass through a proper editor. It was annoying.
Gabe is okay but is like she is so smart and then she does the absolute most idiot things ever. Rafa is sort of hot at the beginning but his constant refusal to properly teach or talk to Gabe about anything is a huge turn off. Their relationship is okay but most of their conflict rely on either of the characters doing really stupid and dumb ass stuff. The Rephaim are all assholes. Mags, Gabe's friend, might as well be a cardboard cutout for all the personality she has and one can say the same for the supporting cast.
The only really good part of this book is the concept and mythology involved but really if you are really picky no amount of awesome concept or mythology will save this book. In conclusion, I am severely disappointing in this book, I thought it would be better but in the end it barely managed to rise above all other UF YA out there.