Introduction
Sigurd was the son of Sigmund and Hjordis, raised and trained by the smith Regin after his father's death in battle. Regin reforged the shards of Sigmund's broken sword into the blade Gram, with which Sigurd killed the dragon Fafnir and claimed Andvari's cursed hoard.
Family
Brynhild and the Fatal Deception
After slaying Fafnir and Regin, Sigurd rode through a wall of enchanted flame to reach the valkyrie Brynhild, sleeping under a spell, and the two pledged themselves to each other. Traveling on to the court of the Gjukungs, Sigurd was given a potion of forgetfulness by the sorceress-queen Grimhild that erased all memory of Brynhild; he married Grimhild's daughter Gudrun instead, and — still under the potion's influence — took on the disguised shape of Gudrun's brother Gunnar to ride through Brynhild's flame wall a second time and win her as Gunnar's bride.
Death
When Brynhild later discovered the deception, feeling doubly betrayed, she goaded the Gjukung brothers into killing Sigurd, which they accomplished (in most versions) through their younger half-brother Guttorm, who was not bound by oaths of blood-brotherhood to Sigurd. Sigurd's death, and Brynhild's own suicide on his funeral pyre soon after, mark the tragic center of the entire cycle.
The Volsunga Saga and the Poetic Edda preserve the Norse-Icelandic form of this legend; the German Nibelungenlied recounts substantially the same events under different names (Sigurd as Siegfried, Brynhild as Brünnhilde, Atli as Etzel/Attila), reflecting a shared Germanic legendary tradition rather than a single fixed text.