I'm going to try to make this kind of not spoilery.... 
 I feel like this 4th installment is really a turning point for the series. It feels like the beginning of the end. In The Fall of Five, we finally find the titular character, Five. Right off the bat there's something kind of off about him. It was like everything he said seemed rather peculiar. Like when he said that he'd never seen a Mog... come on. Those things have been hunting your kind for only your entire life! Something is rotten in the state of Denmark... 
 Much of this book was about finding one another and training and trying to decide a plan of action for the future. There wasn't much in the action department except for short bursts. This was more for character development. We learn a lot of new secrets and meet a few new characters. 
 Ok... from here on everything I say will be spoilery so read at your own risk: 
 (view spoiler)[SAM!!!!!!!!!!!!!!!! I'm so glad he started narrating. I have a special place in my heart for him. He's so brave. He finally found his dad! Well his dad found him with Adam... A MOGADORIAN WITH LORIEN LEGACIES!!!!!!!!! John even says at the very end, "If the Mogadorians have one of us working for them, we might as well have one of them working for us." Perfect. 
 O, and by the way, FIVE IS A JERK-FACE TRAITOR! He kills Eight and betrays them all! Jeez these poor kids can't catch a break. 
 Having to watch Eight die, Marina develops a new legacy through her rage. Now she's like this ice queen who can control and create ice. She stabs out Five's eye and tells him "If I ever see your face again, you traitorous bastard, I'LL TAKE THE OTHER FUCKING EYE!" I love Marina. I hate to see her hurting but that was badass. Considering the next book is called Revenge of Seven, I think it's safe to say that she's going to keep being badass. 
 Ella is Setrakus Ra's daughter. How did Ralen, a Lorien, become a Mogodorian leader? This is all so weird. I assume they will delve into this more later... (hide spoiler)] 
 Ok... geeking out complete. On to Revenge of Seven. I love me some Marina, and I'm looking forward to her being a badass!