Blade Of Ghosts

This book is a fantasy book that takes place in a world where humans live in canyons. It follows a group of humans, stuck inside a valley under constant siege from horrific enemies. The humans explore caves to find useful items like weapons from previous civilizations, who have all been wiped out by the monsters. The monsters come out of a cave and attack their valley, and the humans fight back in a war that has been going on for hundreds or thousands of years. The humans have a power where they weave shadows and use them to attack. One day, a lowly pastfinder named Jason who collects weapons and relics for the army discovers a secret tower, and gains the ability to weave shadows from the past. His weaving is more dangerous and powerful than normal weaving, and he goes on a quest to save his valley. 

I would rate this book 9.75 out of 10 because it was a page-turner with a unique and interesting plot, and the writing was done well.