Shadow Lands (Warrior Chronicles #3), Paperback/K. F. Breene

In order to finally claim her title of Chosen and lead the Shadow People out of the Land of Mist, Shanti must make it through a century's old system to test her battle awareness, her fighting skill, and her ability to stay alive. She's about to enter The Trials, and she must do it alone. Separated from Shanti on a dangerous island, Cayan must learn to use his mental skill while keeping his men safe from the people set out to kill them. But as more Inkna and Graygual flood the island, Cayan hears of a sinister force deep in the woods, rigging The Trials and killing any who venture too close. It is now a race against time. The battle to become the Chosen has begun, and the victor is anything but decided.