3 and a half stars I think. I really liked the book but I believe it did not quite meet its potential. I wish it were a bit longer and the story bit more developed. Alas as it is not the book feels rushed in places and the main character a little bit underdeveloped and you wonder how he got emotionally from A to B. Then again I'm comparing Hellbound with Convivium which was a very long book :) If you liked Convivium you want to check this book out.
I got the book for free in a deal at Amazon and am planning to get myself the sequel.