From BiblePortal Wikipedia

Siegfried [1]

A hero of various Scandinavian and Teutonic legends, and especially of the "Nibelungen Lied" ( q. v .), was rendered invulnerable by bathing in the blood of a dragon which he had slain, except at a spot on his body which had been covered by a falling leaf; he wore a cloak which rendered him invisible, and wielded a miraculous sword named Balmung ( q. v .).