Although Faunehm is from Nidhogg's brood, she became Vedrfolnir's consort who was from Hraesvelgr's brood. When the Dragonsong War began, Vedrfolnir fought with his brothers alongside Ishgard's knights against the Nidhogg horde. In order not to fight Faunehm, Vedrfolnir asked her to flee to the east. Faunehm travels to Othard and stays in Azim Steppe. Because she has resisted Nidhogg's choros for so long, she loses her senses and gives in to her instincts.
When the war is finally over, Orn Khai and the Warrior of Light set out on a quest for Faunehm. Following the rumors of a mighty dragon hunt, they meet Faunehm in Azim Steppe, the pair team up with Estinien Wyrmblood and together fight with Faunehm to get her senses back but this role ends up for Vedrfolnir who appeared during the confrontation.
Faunehm returns to Zenith with Vedrfolnir, and at Orn Khai's request, she tells the story of what Nidhogg was like in his days of honor.
Faunehm is fought twice during Dragoon questline in the Stormblood expansion. The first battle being during the Dark as the Night Sky quest where the Warrior of Light needs to find her in the fog and defend Orn Khai. The second battle is during the Dragon Sound quest and alongside Estinien, the Warrior of Light needs to weaken her.