Scientific name -- Draco niflheimus
Size -- 20' wingspan
Diet -- corpses, roots of Yggdrasil

In Niflheim, the Norse Underworld, lives a great dragon or serpent, Nidhogg, whose name means "tearer of corpses". He gnaws on the roots of the world ash, Yggdrasil, waiting for Ragnarok. Yggdrasil is also home to an eagle and to an anthropomorphic squirrel named Ratatosk. Ratatosk ferries insults back and forth between Nidhogg at the ash's roots and the eagle living up in the branches.

Other dragons tasked to destroy the world tree are Grabak, Grafvolluth, Goin and Moin.