Cardmaster — Clayton Emery

The demon-haunted cardsmith's apprentice Byron struggles with his limited skills and attacks from mysterious enemies.  And when he comes into the possession of some very hot magic-bearing cards, he draws the attention of the cardmaster Cerise.  Soon they're off to the Great Game up in the mountains for virtual "war across the table".  Gangs of cardplayers will battle with sprawling card decks simulating armies and supplies and terrain.  The prize is leadership of three small kingdoms.  If Byron and Cerise can stay alive.  If the leaders aren't assassinated by a spying traitors.  And if the pillaging hordes of the Shinyar don't ravage the valley first!