A Betrayal in Winter book by Daniel Abraham

As a boy, Otah Machi was exiled from his family, Machi's ruling house. Decades later, he has witnessed and been part of world-changing events. Yet he has never returned to Machi. Now his father--the Khai, or ruler, of Machi--is dying and his eldest brother Biitrah has been assassinated, Otah realizes that he must return to Machi, for reasons not even he understands.

Tradition dictates that the sons of a dying Khai fall upon each other until only one remains to succeed his father. But something even worse is occurring in Machi. The Galts, an expansive empire, has allied with someone in Machi to bring down the ruling house. Otah is accused, the long-missing brother with an all-too-obvious motive for murder.