The Elfstones of Shannara
book
Ancient Evil threatens the Elves: The ancient tree created by long-lost Elven magic, is dying. When Wil Ohmsford is summoned to guard the Amberle on a perilous quest to gather a new seed for a new tree, he is faced with the Reaper, the most fearsome of all Demons. And Wil is without power to control them....