The Darkness Outside of Us should have stayed as a stand alone. I was very much looking forward to this book after enjoying that one so much, but it failed to come even close to my expectations.

There are four different POVs in this book and every single one reads the same. They might all have different wants but there is no distinctive voice, even for the two original characters that are supposed to be more fleshed out.

There is also faulty science in this book. As an example, the author claims a singular mammal species survived the extinction event that killed the dinosaurs, which appears to be a misinterpretation of the fact 9 in 10 mammal species went extinct then (https://www.bbc.com/future/article/20220812-dinosaur-extinction-why-did-mammals-survive). There is another situation regarding excess testosterone, which has more side effects than the author seems to acknowledge. There are other instances but these are the first two to come to mind, as well as the ones I am more familiar with.

Finally, while it was not mentioned in the last 2/3 of the book, Owl mentions at least 4 times in the first 100 pages how much she hates being the only person both capable of and possibly expected to carry a kid and co-parent with her brother. It is never mentioned again after that to my knowledge despite this. It's admittedly very odd and out of place with the rest of the book.

Overall, this book was not worth it, and I am not entirely sure the author knew what he was doing for a good chunk of it.