The Mages of Starsea - The Starsea Cycle, #1

A mage's fate is worse than death... Lucian dreams of a new life outside the cesspool of Earth. Unfortunately, his wish comes true when the government identifies him as a mage. No one knows why the mages are being born. No one knows why their powers lead to madness and death in a terrifying disease known as "the fraying". The only solution is to quarantine the mages in academies. When Lucian is exiled from Earth, he must travel to the distant world of Volsung to receive training.
During the long passage, he meets a mysterious mage. She prophesies Lucian is marked by the Manifold, the reality that is the source of all magic. It is a destiny that requires Lucian to master abilities he never imagined he possessed. But that's the last thing Lucian wants. He faces a terrible choice. To accept his new reality as a mage. Or, to try and outrun destiny...