Fafnir is a son of the dwarf king Hreiðmarr and brother of Regin, Lyngheiðr, Lofnheiðr and Ótr. After being affected by the curse of Andvari's ring and gold, Fafnir became a dragon to guard his treasure.
Sieg, obtaining Siegfried's heart, is overwhelmed by the dragon blood during the Great Holy Grail War and fights Fafnir in his dreams. It begins to kill him later, but he uses the Holy Grail to accelerate the process and take on Fafnir's form.
Orleans: Wicked Dragon Hundred Years' WarEdit