Diana L Paxson 
Silverhair the Wanderer 
Book Three of the Chronicles of Westria

Once he had been Farin of Hawkcrest Hold. Then he had been known as Farin Harper, Knight of Westria. Now he is simply Silverhair the Wanderer. Protected only by his sword, his harp and his songs, pursued by a powerful enemy, the path he must tread leads among goddesses and ghosts, man-monsters, madness and shape-shifters, through the palaces of royalty and the tents of ragged nomads. Yet his goal remains unseen, elusive, a mystery beyond solution. He seeks his beloved sister and her son, the heir to the throne of Westria, and they have vanished without a trace.