Guardians of the Lost by Margaret Weis, Tracy Hickman (2001, Hardcover, Illustrated)

Two centuries have passed since a piece of the Sovereign Stone -- the portion belonging to the humans of Loerem -- was lost. Now few on this world shared by many antagonistic races remember it ever existed. But there is one who can never forget: Gustav, a human Dominion Lord, who has made it his life's work to find the missing sacred artifact.

Success, however, costs Gustav dearly. Having at long last recovered the magical relic, he is set upon by a black knight -- a dark servant of the immortal Vrykyl lord Dagnarus -- and is struck a mortal blow. But before he dies, the brave Dominion Lord passes the Stone on to Bashae, a pecwae youth, who agrees to carry it to safety, unaware of the power of the object in his possession...or the hideous strength and bloodthirsty determination of the evil forces who would wrest it from him.

And, with the quest of an unsuspecting boy, the battle for the future of Loerem begins -- a conflict that will ensnare dwarf, human, elf, and orken beings, as Dagnarus launches terrible war from the blackest depths of the Void. Monsters are his army and treachery his most powerful weapon, as the insidious lord ably stokes the long-smoldering fires of animosity that divide the races, creating traitors and villains at every turning, who abet the havoc his demonic minions intend to wreak.

But his foes know all too well the grim price of submission, as heroes emerge from unlikely corners to deny Dagnarus the awesome powers of the Stone. A gruff dwarf seeking riches; the mad daughter of a Trevenici chief; a cunning and beautiful elven Dominion Lord; an imprisoned warrior; an old woman powerful in pecwae magic; Bashae's friend Jessan, who unwittingly carries doom in his pocket; as well as young Bashae himself, who will be tested to the limits of endurance and discover a strength beyond his years, are all players in the epic clash of malevolence versus right.

Yet ultimately the destiny of an embattled world rests on unlikely shoulders. For there is one who passed the trials of the gods, yet rejected the mantle of Dominion Lord -- an enigma whose motives are unknown even to those closest to him, and who now must bear the great onus of salvation...or dire defeat.