Sky's End - Marc J Gregson - Bog

"Exiled to live as a Low, sixteen-year-old Conrad refuses to become heir to his murderous uncle. But Meritocracy is a harsh and unforgiving rule on the floating island of Holmstead, and when his ailing mother is killed by monstrous gorgantauns, Conrad cuts a deal to save the only family he has left. To rescue his sister from his uncle's clutches, Conrad must enter the Selection of the Twelve Trades. Hunter, the deadliest of all the Trades, gains a fresh recruit with Conrad. Now he must endure vigorous training, manipulative peers, and the Gauntlet--a brutal final test that yields riches and status to whichever skyship crew kills the most gorgantauns"--