Elves: The Keeper of the Roots (Elves #22)

Bëloenn, as The Keeper of the Roots, watches over the forest and the ancient trees within. He lives as a hermit until the day when Laëdyss, a young hunter whose clan has been slain, comes to him for aid. Everywhere across Arran's lands, the creatures of the woods are being driven into madness and attacking the Wood Elves... The origin of this evil spreads its malice across the forest of Duhann and far beyond, branching out from the sanctuary of Queen Ora, Guardian of the Green Crystal.