The Sword of Aldones (Ace SF, 79200)

Lew Alton was returning to Darkover - returning at the command of men who had once been all too glad to see him leave. For Lew, a Darkovan on his father's side, and a Terran on his mother's, had always walked between two worlds, accused by each of belonging to the other, and trusted by neither. Yet Lew alone had the power to understand both worlds and to save them from each other's unknown forces. That was the reason he had returned at last - armed with the legendary sword of the Sharra matrix, whose destiny was to cross forces with the equally mystic Sword of Aldones in one mighty battle that would decide Darkover's fate . . .