Wasted potential and simplistic problem solving made this a frustrating read, indeed. Characters who act out of character made it worse, and Adelina is NO hero, with a possible mental condition that no one knows about to boot. 
 Let's begin with the wasted potential part. Adelina was said to be a tortured individual, and we certainly see that her father's influence has affected her negatively. However, I'm led to believe in large part that her terrible attitude comes mostly from dark powers stoked by an affinity for fear and pain, much like elemental affinities in some Eastern traditions, which she can feed off of. Being a creature of darkness, I expected a more fleshed out girl with morbid curiosities nurtured by her father's evil intentions. Furthermore, I expected since rebellious behavior in early childhood. Instead we get a confused girl whose aforementioned darkness causes her to make nonsensical decisions, and who allows people to talk to her any kind of way. She hates her sister for no good reason, keeps dangerous secrets for no good reason, and we're expected to side with her. 
 Oddly, Adelina acts a bit like she has a mental disorder; she heard voices, sees thing that aren't there, and fails to be able to think through problems in a long term way. She also loses her temper easily, only to fall into confusion soon after. She breaks down frequently, in terrible situations. Although the book blames these things on fear and her powers, it seems that her condition sprang from trauma, and being able to create illusions has simply exacerbated her condition. It is because of this that, early on, I decided Adelina was the bad guy, and that made for a more interesting read. This is a girl who entered the fold of a secret society, and proceeded to be offended that everyone didn't trust her right away. That have zero fucks about earning trust, and instead did everything in her power to lose what little she gained. Who repaid her saviors by ruining everything they held dear. And yet she let people talk down to her any kind of way? Girl, please! Get real. 
 The worst part is that I had to connect all this shit together myself. Lovely. Adelina... honey. If only she had been written to be struggling with a mental disorder, I could get with her, but right now, she's a confused caged animal, and she's going to destroy more due to ignorance and naivete. 
 I almost want to read the next book to see the impending shitstorm unfold. 
 EDIT: Downgrading to two stars. After some time, I dislike it even more.