The Black Prism

A group of semi-autonomous countries around a sea, the Seven Satrapies, is the setting of the first novel in Brent Weeks's five-volume Lightbringer series, where drafters turn light into a substance called luxin. Gavin Guile is the Prism, high priest and emperor and the mightiest man in the world, and his wit and charm are what keep a fragile peace. Prisms never last, and Gavin knows how many years remain to him. Then he learns of a son, born in a distant kingdom after the war that raised him up, and must weigh what he will give up to guard a secret that could break his world apart. The novel was first released in August 2010.

Brandon Sanderson put it on his list of books he suggests to fans.