I picked up a copy of this book because of the hype that surrounds it, and I was surprised to find that it lives up to it! Obsidian is the first book I've read by this author, and I enjoyed it so much that I've already put in pre-orders for books 2 and 3 of this series. It features an interesting take on aliens, a refreshingly level-headed heroine and lots of action and drama and heat between the two main protagonists.Katy is an awesome YA heroine, an opinion I formed early on because she is a fellow book blogger. The very first page tells us about her love for books and the addiction she has to her blog. The very first scene has Katy wearing a T-shirt blaring the words "MY BLOG IS BETTER THAN YOUR VLOG". Here is a heroine that I immediately connected with! I've always said that with all the books I read I would react to anything paranormal very differently to the average YA protagonist, and Katy proves this point with her reaction to Daemon's extraterrestrial origin. She also knows when she is being treated badly by Daemon. Even though he's hot and she can't deny that Katy is physically attracted to him, she recognises that they don't get along well and refuses to entertain the idea of a functional relationship between them. But there is a strong sexual pull between them, even though they can't stand one another, which provides a constant source of exasperation and humour.My favourite character in the book is Dee - Daemon's twin sister who quickly becomes a close friend of Katy's. She's loud, energetic and has an awesome personality. I think I would get along with her really well. Most of the other supporting characters blend into the background for me - Katy's human friends at school aren't particularly interesting and the Luxen are quite confusing because there are so many multiple births in their race and I had a hard time keeping track of all the twins and triplets.Obsidian is very well-paced and has a plot that kept surprising me. Katy is an observant narrator, and although she sees a lot of inexplicable things, she isn't ever dumb about them or jump to stupid conclusions. She reasons through things and comes up with the same explanations that I would come up with in her situation. There is a lot of action in this book, and, again, I was impressed with how Katy reacts to it. She is brave without seeming silly or suicidal, and doesn't make decisions that end up creating more trouble than preventing it.Obsidian is a gripping, fun read that impressed me greatly and I am eagerly awaiting the publication of the rest of the books in the series, including a prequel novel that is being released soon. I think fans of YA fiction will love this book - it is certainly more enjoyable than the only other YA alien book I've read: I am Number Four.You can read more of my reviews at Speculating on SpecFic.