Veðrfölnir is a hawk situated on top of the world tree. Presumably, its purpose, like that of Odin’s ravens, is to acquire knowledge. The four harts, Dáinn, Dvalinn, Duneyrr, and Duraþrór, eat among the branches of the world tree; each stag connects with the seasons or phases of the moon. Níðhöggr is a dragon that gnaws at a root of Yggdrasil. “Níð” is a term for a stigma that implies the loss of honor. Thus, the name refers to its role as a monster or in its action of chewing corpses of those guilty of murder, adultery, or oath-breaking.
Kalos Legendaries, by Nick.