The broken eye (#3) Lightbringer series
(Book)

As the old gods awaken and satrapies splinter, the Chromeria races to find its lost Prism, the only man who may be able to stop catastrophe. But Gavin Guile is enslaved on a pirate galley. Worse, Gavin no longer has the one thing that defined him -- the ability to draft. Without the protection of his father, Kip Guile will have to face a master of shadows alone as his grandfather moves to choose a new Prism and put himself in power. With Teia and Karris, Kip will have to use all his wits to survive a secret war between noble houses, religious factions, rebels, and an ascendant order of hidden assassins, The Broken Eye.