Rating: 4/5 
 ***Minor spoilers, big spoilers for book one!*** 
 Onyx begins shortly after Obsidian ended. Daemon and Katy are just beginning to learn what their new connection due to Daemon's healing of her does. They're becoming closer and are undeniably interested in each other, but Katy is unsure if this is due to the new connection. Not long into the book, we learn that the Department of Defence is in town and they're suspicious, like always. This isn't really good for Katy, who's starting to have some weird alien abilities of her own due to her bond with Daemon. If she isn't careful, she may expose herself to the DOD and put all of the Luxen in danger. 
 I thought this book was much, much better than the first. The only reason I didn't rate this higher is because Katy really annoyed me in this book. There was a bit of a love triangle that I can't even call a love triangle because Katy doesn't even actually care for the other guy. She continues to lead him on because she doesn't want to confront her feelings for Daemon. She's was hurting both of them in a way and she seemed so oblivious to it, or maybe she just didn't care. I just wish she spoke to Daemon sooner. 
 I thought the prospect that Katy was getting Luxen abilities because of their bond was pretty interesting. It was also believed that since Daemon is super strong, she would be super strong as well. My issue was that Katy didn't seem to want to train with Daemon, but instead wanted to train with another new kid in town named Blake, who was a "hybrid" like her. I have no idea why she didn't want to learn with Daemon, who she knew she could trust with her life. It also seemed like everything Blake was telling her, Daemon could've done as well and been a lot nicer about it. Some of Katy's decisions in this book just didn't make sense to me. 
 My favourite thing about this book was probably the connection between Daemon and Katy. Things were getting more romantic between them and they were able to be in the same room for a long time without fighting. They seemed to have a new respect for each other and a new trust that I really enjoyed. I only with that we got to see more of their romance. If only Katy didn't have to run to Blake all the time. 
 Overall, I loved this book a lot, more than Obsidian. The plot was more interesting but I actually disliked Katy more in this book. I'm hoping that in the next book Katy isn't as idiotic and will actually listen to the opinions of other people. Regardless, I'm excited to continue on with this series when I can.