What is fafnir in Final Fantasy XII?

To find fafnir u have to follow a certain path in the paramina rift..Speak to Relj to make the blizzard appear in Paramina Rift, then from Mt. Bur-Omisace, head to: Freezing Gorge -> Head of the Silverflow -> Icebound Flow -> Karydine Glacier -> Silverflow's End. This path is the only way to continue the blizzard and thus the only way to find Fafnir