Witch Wraith. The Dark Legacy of Shannara

From bestselling author Terry Brooks comes the final thrilling novel in a brand-new trilogy-The Dark Legacy of Shannara!  NEW YORK TIMES BESTSELLERFor centuries the Four Lands enjoyed freedom from its demon-haunted past, protected by magic-enhanced borders from the dark dimension known as the Forbidding and the profound evil imprisoned there. But now the unthinkable is happening: The ancient wards securing the barrier between order and mayhem have begun to erode-and generations of bloodthirsty, monstrous creatures, fueled by a rage thousands of years in the making, are poised to spill forth, seeking revenge for what was done to them.
  Young Elf Arling Elessedil possesses the enchanted means to close the breach and once more seal the denizens of the Forbidding in their prison. But when she falls into the hands of the powerful Federation's diabolical Prime Minister, her efforts may be doomed. Only her determined sister, Aphen, who bears the Elfstones and commands their magic, has any hope of saving Arling from the hideous fate her captor has in store.
  Meanwhile, Railing Ohmsford-desperate to save his imprisoned brother-seeks to discover if his famed but ill-fated ancestor Grianne is still alive and willing to help him save the world .