The myths of the Norse, also called the Vikings, are replete with heroes--among them Baldur, god of light and purity, Thor, who slew giants and other enemies of the gods with his invincible hammer; and the courageous Sigurd, nicknamed the Dragon-Slayer. Opposing the heroes were several villains, including Loki, who repeatedly betrayed his fellow gods, and Hel, who ruled an underground domain of dead souls.