Exile's Children by Angus Wells
First in an epic two-volume fantasy,EXILE'S CHILDREN tells of a people split asunder by a love-match,of a community and a culture rive by dissent and disaster,utterly unprepared to counter the all-consuming threat that is approaching from beyond the mountains that form the boundaries of their world.The hope of salvation comes in several forms,in unusual alliance with troll-like dwarf men who live in labyrinthine tunnels and caverns within the mountains,and in a coming together of a band of mis-matched exiles fleeing from very different enemies.