The Revenge Of The Shadow King, by Derek Benz and J.S. Lewis
Protagonist - Max Sumner
A strange creature called a Spriggan, saved Max from tumbling off a waterfall, after that event Max offer to do something for the Spriggan. She told him to let a "small harmless shadow" out of a strange book he found, but as you can see from the picture, the shadow was the exact opposite of what she said...
Antagonist - Oberon / Shadow King
On some days Max and his three friends, Ernie, Harley, and Natalia, would play a game of cards called "Round Table." They would play this game in the back room of a antique store owned by Max's grandfather's best friend, Iver.
Conflict - Character vs. Character
Maximilian Sumner was born into a rich family that owned almost everything in Avalon Minnesota. Max is liked by almost everyone in his school, but it is not for his money. The reason most like him is for his lack of fear and his outstanding courage.
Wise and terrible. Deadly and Ruthless. He's the cruel and unimaginably powerful ruler of the Shadowlands of Faerie.
Oberon wants Max's magic book, so he can let the other monsters out and open portals from their world to his, all the while destroying both worlds.
Curiosity may have killed the cat, but Satisfaction brought it back