The Elves and the OtterskinElizabeth Boyer1981

Ivarr had been sold to the witch Birna. But now Birna was dead, slain by the evil sorcerer Lorimer. Ivarr was stranded in the land of the elves. His only chance to return to his own realm was to become a hero for group of outcast, incompetent elves and a wizard of doubtful qualifications.
As he discovered, being a hero was a little difficult. First he had to seek out a magic sword concealed somewhere in the land of the fire giants. Then, to seize a horde of gold, he must somehow find and destroy a terrible dragon. And, finally, he would have to overcome the power of Lorimer and an army of dark elves.
Ivarr knew nothing about being a hero, and the more he heard, the less he liked the idea. But a hero he'd be--or else!

Titre original : The Elves and the Otterskin (1981)