The Fire Within Them - Matthew Ward - Bog

The sprawling Kingdom of Khalad stands alone. Severed from the rest of the world by an ancient, arcane war, its folk toil behind a wall of living mist, beholden to an undead king and his barons. But hope lies with two figures: Kat, an accomplished thief, and Vallant, a rebel and folk hero. Together they will light a fire that will burn away the corruption and tyranny of King Diar's rule. But only if they succeed . . .