In the end, I am glad that I saw it out to the end of the series. This last book was much better than the previous two books, and better than The Last Colony. 

I did find myself comparing it to the Bartemeaus Trilogy, which I liked quite a bit better than Artemis Fowl, and then I realized that the Bartemeaus Trilogy was published first. 

But this was a great conclusion to Artemis Fowl's story, and I'm glad I read it, though I can't justify even so much as a four star review: Artemis again has multiple moments in this story where he just acts like an idiot instead of a boy genius, and the book suffers with the same continuality errors that the last three books have. Artemis doesn't understand military signals that he clearly explains in previous books, events of the previous books are brushed under the rug to be forgotten about completely, etc. etc. 

And wow, I don't know what Colfer has against dogs, but there was a lot of dog death in this book (and it reminded me that there was even some in a previous book too. The Time Paradox, maybe?)

final thoughts: nostalgic to go back to this series and pick up where I left off as a kid. series is overall fun and entertaining, but grating/eyeroll-worthy in parts. this was not helped by nathaniel parker's racist "asian" voice for opal on the audiobook. 
still, the characters form meaningful bonds and there's suitably emotional payoff.