The Great Tree of Avalon, Book 1: Child of the Dark Prophecy (Merlin Saga, Band 9)

Long ago, the great wizard Merlin planted the seed that would become the peaceful world of Avalon. Now, though, Avalon is suffering from mysterious droughts. Then the very stars begin to lose their light, and it seems that the Lady of the Lake's dire predictions are about to come true. The fate of Avalon now rests with Tamwyn, a wandering wilderness guide; Elli, an apprentice priestess; and Scree, a young eagleman. One of them is the true heir of Merlin, the only person who can save Avalon . . . and one of them is the dreaded child of the Dark Prophecy, fated to destroy it.
As in his acclaimed epic The Lost Years of Merlin, T. A. Barron has created a radiant, richly imagined world, full of high adventure and un-forgettable characters.