Dalglish, David. Vagrant gods #1

"Cyrus was fourteen when his gods were slain, his country invaded, and his parents--the king and queen--beheaded in front of him. After years held prisoner in the invader's court, a mysterious group of revolutionaries breaks him free and gives him the chance for revenge that he's always dreamed of. In exchange, he will become the figurehead of their rebellion. He will become a hero to unite the people and strike fear in the hearts of the imperials. He will take up the skull mask and swords to become the legendary "Vagrant"-an unparalleled assassin of otherworldly skill. But all is not as it seems. Creating the illusion of a hero is the work of many, and Cyrus will soon discover the true price of his vengeance"--