Fafnir - dragon
Fafnir is one of the frost giants with whom the gods are in constant conflict. Wotan bribes two of the giants, Fafnir and his brother Regan to build Valhalla stronger walls. Wotan promises to give them goddess Freya as payment. This promise leads to all kinds of complications and woes. In the end Fafnir transforms into a dragon to protect his treasure.