Preface: I received a copy of this book for free in exchange for an honest review.
If I could do half stars, I'd give this a 3.5. It's not great. It's not terrible. It's just perfectly adequate fantasy for most of the novel, until about the last fourth, where things really pick up.
Shadowborne is the story of two brothers, William and Madigan, who are raised by their grandfather after their mother is tragically killed. Their grandfather raises them on stories of a fantastical land filled with light and darkness. The boys assume the stories are just that, stories...until William begins to manifest powers of his own.
Honestly, there's not a ton to say. The writing style is decent, if a bit overwrought at times. There are some good descriptions and turns of phrase throughout, but it has some common pitfalls as well (namely, character tics. Lots and lots of smiling and chuckling and winking). At the same time, there's some good stuff in here. The worldbuilding is interesting (though a lot is not elaborated on, probably due to this just being set-up for the trilogy), as are most of the characters aside from the main two.
The brothers are one of the main problems in the story. They're just not particularly interesting, and they're really hard to differentiate at first until Will's love interest is introduced. Her arrival finally sparks a difference in the brothers - namely how they react to her - that the novel builds on. (The love interest herself I do not care for, but I won't get into that.) Prior to that, they're just your typical boys wanting to be heroes.
The other big problem is the pacing. The first half is really bloated with stuff that just doesn't matter. Pages and pages of summary on their childhood and training. Pages of them preparing for their journey (and then all that preparation going to waste when they're immediately met with disaster). Pages of them being cooped up in a tower. Things really don't pop off until the last fourth - and then they get really, really good. Without any spoilers, I can't say much, but I will say a very interesting character is introduced near the very end of the novel, one who really infuses it with a lot more energy and intrigue. The book touches on the relationship between light and darkness, how neither is truly good or evil, but that theme doesn't really get driven home until this character comes into play.
I would be interesting in reading the next book, mostly because a lot of the exposition is out of the way. However, I will say the last chapter is really, really screwy and hard to understand. It just completely throws everything for a loop in a way that isn't pleasant. Again, I assume this is just set-up for the rest of the trilogy, but it was sloppily done and kinda soured things for me right when I was starting to like it.
But, for the most part, this book was perfectly fine. If you just want a simple swords-and-magic romp with two typical teenage boys as your protagonists, this will suite you just fine.