The Chapel of the Wyrm - Fallen Rogues, #3

An invading army. A queen deposed. A city in chaos. A war for Diregloom has begun. When a band of the duke's elite soldiers seize control of the island, Digger discovers he's at the top of their list of wanted men. But the duke has something more in mind for the city besides arresting all who dare oppose his edicts. For Isabel and the sisters of the Black Rock Mission have been protecting a secret.
Whoever possesses what they're hiding will decide the future of the city and all who live there. As for Digger, this means choosing a side in a fight he doesn't want but can't possibly avoid. Grab part three of the dark fantasy adventure from the author of the best selling Goblin Reign series!