Fafnir

In Norse mythology, Fafnir was a son of Hreidmar and brother of Regin and Otter. After Otter was killed by the Aesir, Hreidmar received the cursed gold of Andvari's as repayment for the loss of his son. Fafnir and Regin then killed their father to get the gold, but Fafnir decided he wanted it all, turning into a dragon (symbol of greed). Regin then sent his foster-son, Sigurd, to kill the dragon. Sigurd succeeded, but then killed Regin too, upon learning that he had planned to kill him once he had recovered the gold.

As Fafner, he featured in Wagner's Der Ring des Nibelungen.