Thank you to Netgalley and the publisher for providing me with this book in exchange for an honest review. This did not influence my review in any way. 
 I have never really loved the Elementals series. I have enjoyed reading the stories of the Merrick boys and Hunter, and I felt this series had a lot of potential to be MORE than what it was, but I never fell in love with it. And if it ever lived up to the potential, I didn't want to miss that because I felt the Merrick boys were extremely well developed characters and I really liked the Elemental storyline. In this last book, I was looking forward to an epic showdown, lots of action, stakes high. I expected it to maybe come around full circle and while a happy ever after wasn't realistic or necessary, I still wanted a satisfying ending. 
 I should not have expectations. I should not think about how I want a series to end because I will only ever be disappointed or unsatisfied. I think unsatisfied is a good way to describe how I feel about the last instalment to the Elementals series. 
 It's the one I've been waiting for, really. Michael Merrick is not an impulsive or reckless teenager like his younger brothers, he is 23 years old and carrying responsibility beyond his years. Trying to keep his brothers out of trouble and keep them safe from the Guides who don't want the full Elementals to exist while running his father's landscaping business, Michael is starting to feel the pressure. But the Guides have decided that they have waited long enough for the Merricks to trip up. It's time to end this. The war is coming. 
 I found Sacrifice to be quite anticlimactic. It's the last book, the final one, and this is how I'm going to remember the Merricks, because I'm not sure if I will actually ever revisit this series (too many books, so little time). And I'm going to remember the last book as a let down. This book follows the same formula as the previous four, which I expected to a point. But I didn't expect to see so little of the secondary characters we had been introduced to in previous books - Becca, her ex-Guide father and Quinn were only mentioned in passing and Layne only spoke one or two words, her brother only there in the background. We did instead have Tyler and Adam, and I wonder if this is due to the strong audience reaction to those two, rather than the natural progression of the story. Is the author just capitalising on what she thinks the readers want? However, I can see how having Tyler and Adam in the story makes sense as they both have conveniently absent parents. They are also a little bit older than the younger Merrick brothers, who were also fairly absent for most of this novel. This, I think, while a bit disappointing because I wanted to see all of them, also made sense as it highlighted how alone Michael had become. 
 Sacrifice completely changed how I originally had seen Hannah. I didn't like who she was in Sacrifice. She was immature and took unnecessary dangerous risks and threw tantrums at her parents. Really? You are raising a young child and you're the one throwing a tantrum. Even if you didn't have a child, you're twenty two years old! You're too old to be throwing tantrums. It's a commentary on the writing of this series that I haven't really liked any of the female characters and this was really disappointing, especially when the males were so well developed but it feels like no time was taken with the girls. I also think the 'almost love triangle' was extremely weak and I wonder why it was even a thing, the fact that Hannah was entertaining thoughts like that makes me question whether her and Michael should be together. 
 As for the storyline, the action scenes were just not what I was hoping for and were lacking in intensity and the ending felt incomplete. The series didn't feel like it was finished, it didn't all come around full circle and we are still left with a feeling of uncertainty for the boys' futures. While I understand that this is an accurate representation of life and things don't always wrap up nicely, as a series I felt it needed to be more wrapped up. It felt like just another Elemental book in the series and there wasn't really anything that made it stand out as the series final. That being said, for the sake of completeness I will most likely go out and buy a copy for my bookshelf but I'm unsure if I will recommend the series as a whole. But when the boys are so well developed as characters, which seems to be rare among this genre of YA fiction, it's hard to say that you should discount them altogether. I only wish this series had delivered to its full potential and I wasn't left with just another okay read.