I think I'm still in shock. 
 This is probably going to be very long, and there will be spoilers. So if you are reading series now or are planning on reading it at all, it's probably best not to continue on. 
 I'm going to be completely honest. I sometimes try to stay away from a series, especially if it's a longer one (longer to me being five or more books). It's not because it's too much commitment or too much reading. It's because a series will draw you in. It will make you connect with characters on a much deeper level because you are able to see the character development that you wouldn't be able to read in a single book or even a trilogy. A character might go from being your absolute least favorite, to your number one favorite. That's not because you suddenly changed your mind, but it's because along the way the development made you realize that you connect to this person and their part of the story on a much deeper level. (Basically I'm talking about Caine here) 
 As a reader, I always tend to fall in love with minor characters. I don't know if this is because they don't have the same kind of development you see with main characters. Maybe it's because main characters get on my nerves. But minor characters and their arcs usually grab me and then break my heart. (Edilio....I just love him). 
 Now on to the actual book. I bought it yesterday, started it around 5 and finished it this morning at 11. It went very very quickly, and the pace was very fast. There was no slow beginning (which I struggled with in Hunger and Plague. I don't know why. The first 50ish pages in both of those books just were slow for me) and it literally picked up where it left off from Fear. That's great. That's fine. In fact, I had a hard time putting this book down (and when I actually had to, I was not in the best of moods). I do have a problem though. I thought that there were too many....fights? I don't know if that's the best way to express how I feel. But it's close. There was always a conflict happening. 
 I almost wish there had been one less fight. (This is where the spoilers start happening. So if you don't want to know what happened, this is your last warning. STOP reading). 
 Gaia seriously got on my nerves. I know she's the big bad wolf in this series, finally in human form. But. I was a bit annoyed with the repetitive "I'm in a human body and this means I can be hurt... who knew?" It just annoyed me because she kept slouching off after a battle (and then there would be a bit of whining while she healed herself) and then BOOM we're ready for another battle. I'm not saying it doesn't make sense. I'm not saying it was poorly written. I'm just saying that after the third time I was like ...again? 
 Sam going off to fight her so he would die... I mean. That's great. That's very Sam Temple. But I mean it obviously wasn't going to work, and there's no way he was going to die like that, with so much story left to tell. 
 Caine. Oh Caine, you are my favorite. I don't know why. When Caine and Diana were reunited, it broke my heart. That is a couple who I found to be one of the most realistic in the series. Sure, they did horrible things together. Sure, they were selfish. But they are a couple that draws you in hating them, and by the end, you are rooting for them (just a little bit). When he pushed her away in the boat? My heart hurt. The note he wrote her? It broke a little bit more. Him sacrificing himself? #3000%done 
 Then you get to Sam and Caine working together. Again. I LOVED it in the fourth book. I think that seeing these extremely opposite characters work together is amazing. It's fascinating. They hate each other for so long, and try so hard to kill each other, that seeing them work together and support each other... It pulled my heart strings. And the note that Caine wrote to try and help Sam and Diana once they got out of the FAYZ? Hurt even more. 
 When Albert defended the graveyard? That was the only, yes ONLY time that I've ever liked Albert's character. Period. 
 Astrid being the official spokesperson for the kids of the FAYZ? Great. It's the only thing that made sense. This book put me firmly back on the Astrid + Sam bandwagon. I was back and forth this entire series. 
 I still love Quinn, although he did seem to legitimately disappear at some point during one of those battles. I love though, that it was Quinn who scooped up Sam when he was broken, and then helped spring him from the hospital. It wouldn't have been right any other way. 
 Brianna.....it hurts. 
 But, the thing that broke me the most. Game, set, match. Was when Sam was asking Edilio to kill him, and Edilio wouldn't and couldn't do it. Those two are the definition of a team. They are the definition of brothers. When they said goodbye in Fear. I cried. When they had that moment in Light. I cried. 
 Do I love how it ended? no. Did I dislike it? Not at all. I think it is great that Astrid and Sam are almost looking after Diana. Supporting her because it's the right thing to do. I think that that right there is the most respectful way to end Sam and Caine's issues. Caine's note allowed for Sam to walk free. It's the least they could do. 
 That's all. At least for now. I know this is long, but I have a lot of feelings that go hand and hand with this series, and if I didn't go and write them down.....I'd have probably lost my mind.