REGIN In Norse mythology, Regin was the brother of the otter killed by Loki, and also of Fafnir, who was transformed by the power of the curse of Andvari's ring into a great dragon. Regin was a smith, who taught the young hero Sigurd all thearts and sciences, and forged for him a great sword, which which the hero was to killFafnir, that Regin might have the treasures that the dragon guards. But the swordbroke upon its first trial, and Sigurd, in contempt, had Regin reassemble the sword of his father, the great blade Gram. When Sigurd had slain Fafnir, and Regin demanded thetreasure, Sigurd slew him with the sword.