The Lost Prince by Raven Storm

Cast aside since birth and denied my true heritage, they know me as the bastard prince. For years I played their game, doing allI could to assist my half-brothers shuffle refugees from the castle, while keeping them and the dying Nobles safe in the old mine tunnels.
The Prince of Rats, one girl called me. The others view the curse as their doom, but they don’t realize the golden opportunity it presents. With magick coursing through my blood, I’ve greedily hoarded all the knowledge I could. They left us all for dead, and once I’m through with them, they’ll wish they’d stuck around to finish the job. All of Dorea will tremble under the might of their new Overlord.