While I gave it 4 stars it's actually 3.5. While I still enjoy reading about the sisters and like that each book can be read as a standalone, this one was not as good as the first two.

First off, I was reading an ARC and the formatting was atrocious, however, that did no play into my rating. There was just too much;. all the books have had violence and monsters this one had too much of both. The author has a great imagination when it comes to the horrors he puts into his books, but they don't all need to to be in one book.

Since I've already paid for the next book in the series (because I liked the first two so much) I'll continue the story, however, if it's like this one it will be the last.

A Boys Own Adventure to the centre of the World-of the 8th Hell-or the Island Shingora.- from whence no-one ever returns.
The author had bags of fun here creating monsters, or he has seriously bad nightmares and this was his therapy_ to write a story that included the worst. And showed off his knowledge of obscure weaponry too.
Ok- Maybe it's a Girls Own Adventure as most of the men come off really badly in this story. And the women do very well indeed and are not only Amazons, but also the True Chosen [sisters] of the Gods - Allena and Baezha, and who are very heroic.
The nasties didn't frighten me but it's probably not a good read for those of a timid disposition.
Unfortunately there were quite a few proofreading errors, but all small and thus didn't impact too much.
Was it good writing? Well maybe-
Was it well told? Maybe.
Would I recommend it? Depends on reader.
Would I read more? No.

This book had an interesting start. I liked the way people were chosen for this rescue expedition. There were mercenaries from every different craft. I thought it interesting that when Aleena was interviewed she answered all the questions honestly, but even after she got the contract, she still had to prove herself. Her sister, Baezha, went through the same type of questioning, but she was not asked to prove herself. I am sure that this had to do with the conniving weasel that was helping to interview the fighters. He did not like or trust Aleena, so he made her do things to prove she could do the things she clamed she could. None of the other fighters were tested this way.
The trip to the Shingora on the ships was a little slow, but interesting. There were some interesting things that happened along the way that help keep my interest. There were sometimes on the trip that I would have liked to have seen some people end up in the sea.
The real fun began when the ships got to the Shingora. They were attacked before they even got off the ships. The Shingora itself was rather interesting. Estes has a very good imagination. He made his monsters as nasty, disgusting, and creepy. He did well on the description of these monsters and what they looked like.
Even though this book can be considered a standalone book, I recommend reading the first two books in this series before reading this one. I thought the ending was rather abrupt. When this book ended, I was expecting there to be more, but it just came to an abrupt halt.