The Damned: Casca Series, Book 7

In a state of near despair, Casca leaves behind the now dreaded gates of the Persian Empire, and makes his way back to the Northlands. After his ordeal in "The Hold," Casca is summoned back from his crazed state to face one of his most formidable foes, the would-be conqueror of all Europe, Attila the Hun.