I really favor the protagonist of this series, Rhine. She's strong, and she's smart. Granted, for most of this novel she was kind of out of it, either on some drug someone gave her or in a delirious state brought about by illness. But I thought she did what she could under the circumstances. And I appreciate Gabriel a little more; honestly, he just didn't do it for me in Wither. But since he's around a lot more often in Fever, I like how kind he is and how he genuinely loves Rhine and wants to take care of her. I mean, he left behind the mansion, which was all knew, to follow her into this big dark world that is apparently extremely treacherous. 
 I've never liked Linden much. I mean, I realize that he's probably a good person who honestly loves his wives and his family, but . . . eh. I just don't like him. To me, he represents cages and ignorance and a whole mess of other unpleasant things. The thought of him ending up with Rhine in the third book is kind of gross to me. I mean, number one, his true love is Rose. He will never love anyone as deeply or as passionately as Rose. This has been proven to me multiple times. Number two, he has a baby with another woman. In my mind, he is not a good love interest. At all. 
 The villian in this book. Vaughn. He's creepy. He's demented. He's ruthless. And he may be one of the best YA villians I've read in a long time. I mean, I obviously don't like him, but I got that creepy vibe that I only get when I'm reading about a villian who REALLY scares me. Like, if I met him in real life, I'd run screaming from the room. I'm excited to see what happens to him in the third book. 
 I am somehow more disturbed by Fever that I was by Wither, and that's really saying something. Luckily, I can handle dark and gritty themes. Such as the carnival. Madame was also good villian. Not as good as Vaughn, but still. I enjoyed the new characters introduced in this novel, like Lilac and Maddie and Silas. They were all developed really well.