Níðhöggr or Nidhogg (Malice Striker) is a powerful dragon that is found in Norse Mythology. The big mighty dragon lives in the roots of the great ash tree Yggdrasil which holds the 9 realms of Norse cosmology together. Níðhöggr also chews on the roots of the tree for all eternity with hopes to damage it and topple it. He has a rivalry with an unnamed eagle that lives at the top of the World Tree and the two exchange harsh words and messages through Ratatöskr, the giant mischievous squirrel, that bears the words between the two. It is said that the Níðhöggr will go off to Ragnarok, the Norse Judgement day to aid the giants in their battle against the gods.
Níðhöggr is quite large in size, large enough to definitely make serious damage to a tree the size of the universe. He has large dorsal spines on his back and curiously has no wings or even arms or rather he has legs or arms that function as both their primary function and the other. He has two large horns and thick body armor reminiscent of most dragons. Contrary to usual belief. He is not actually a ''dragon'' in the norse sense. In norse mythology. He serves as a ''devourer'' or ''eater''. In norse mythology. These kind of beings were called jotuns or giants. In this sense Níðhöggr is actually a giant in that he is large and is a consumer. Níðhöggr constantly chews on Yggdrasil the world tree at the center of the norse cosmology. Níðhöggr has never left the roots of Yggdrasil. Presumably being born there and living there. His origins are unknown from there. He is in and around roots a lot maybe saying that he is most at home there for whatever reason
In common belief. Dragons are fire-breathing, winged and guarded hoards and (or) ate maidens. Níðhöggr doesn't do this to our knowledge. This already sets him apart from other ''dragons''. In common knowledge, wyverns are two legged dragons. This fits the description of Níðhöggr quite nicely. So in the norse sense he is a giant but in the dragon sense he is a wyvern.
Níðhöggr is not unique in that he is actually one of several other lindworms, dragons and serpents slithering around the roots of Yggdrasil but Níðhöggr is by far the most popular one.
Despite his myth originating in ancient northern Europe, he looks rather like eastern dragons with the exception of him being malevolent in pursuit and mannerism.
Níðhöggr is classified as a lindworm ( if not a giant) which is the technical term for dragons of his body shape in norse mythology. Other lindworms include Fafnir, Grábakr, Grafvölluðr, Ofnir, Svafnir, his sons Góinn and Móinn and the other lindworms slithering around and biting the roots of Yggdrasil.