The Elfstones of Shannara: (#2) (The Sword of Shannara)

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.... From the Paperback edition.