Books in the The Serpent and The Sorcerer Trilogy series

One thousand years after Merlin's death, Avalon stands divided by an enchanted forest. But the magic is weakening. When the last spell breaks, Merlin's descendants will be faced with an old enemy. War is inevitable, and it will awaken something far greater than anyone could imagine. The age of rulers and kingdoms is almost at an end. The White Witch is coming...