Red Moon and Black Mountain: The End of the House of Kendreth

From the description at the front of the book: Kedrinh, the Starlit Land, is threatened by the Powers of Darkness, for Fendarl, fallen Enchanter of the Star Magic and banished Lord of Black Mountain, has in his long exile grown strong enough to challenge the rule of Kiron and the Starborn. His power waxes with the Red Moon, and nowhere in the whole land is there a champion who can stand against him, for the Necromancer bears a charmed life. Into this world come three of our own kind, each of whom has a part to play in the defence of Kedrinh. They learn that victory does not always come with conquest and that something more is necessary, before the Starlit Land is finally safe.