In Norse mythology, Fafnir is the dragon who was once the dwarf Fafnir.
The story appears in the Völsunga saga and related heroic traditions. Fafnir kills his father, Hreiðmarr, to seize a cursed hoard of treasure, including the ring Andvaranaut. The curse drives him into isolation and transforms him into a powerful serpent or dragon guarding the gold.
The hero Sigurd eventually kills Fafnir by digging a pit and stabbing him from below as the dragon crawls over it. Before dying, Fafnir warns Sigurd about the danger of the treasure and its curse. Sigurd then tastes the dragon’s blood and gains the ability to understand birds, according to the saga.
Fafnir is often confused with Níðhöggr, another Norse dragon, but their roles differ sharply. Fafnir is a transformed dwarf connected with a cursed hoard; Níðhöggr is a cosmic underworld creature linked to Yggdrasil.