There are many dragons in Norse mythology. Perhaps the largest is Jormungandr, the World Serpent. The second greatest is Fafnir, who fought the great hero, Sigmund.
But the third largest (and rejoicing in its lowly position) would be Nidhogg (also called Níðhöggr).
Nidhogg the dragon
Nidhogg is a fierce dragon who gnaws at the roots of Yggdrasil , the tree that supports the nine worlds of Norse mythology . This power-hungry monster is sometimes referred to as "The Malicious Attacker", an apt name given that he rules over dark criminals and is bent on destroying peace and virtue.
The name Nidhogg
Like all creatures, gods, and mortals in Norse mythology, Nidhogg's name tells us exactly who he is.
Nīþ is the first syllable of the word Nidhogg, and it plays a very important role in Norse society. You see, nīþ means a social stigma in Norse and Germanic culture. It implies that a person has suffered a great loss of honor and is, in fact, a villain. To be called a nīðing (níðingr/ᚾᛁᚦᛁᚴᛦ in Old Norse, nīðing, nīðgæst in Old English, or nidding in Old Germanic). Modern Dutch and German even have similar sounds that imply hatred, envy or greed.
Nīþ implies rudeness, cowardice. If people called you nīþto your face (and it was expected if you were known to be a niding), you were bound to fight them. You could challenge them to take back their words or you would murder them. On the other hand, if you had no physical contact with the accuser, you were known to be a coward.
What does Nidhoog look like?
Nidhogg is a huge dragon. Its body is covered with shiny scales and horns protrude from its head. A pair of forelegs, fitted with massive claws, help it tear at Yggdrasil's roots, but it has no hind legs, only a serpentine tail. Under his bat wings, he carries the corpses of criminals.
His body can be found writhing in the roots of Yggdrasil, especially around Niflheimr , the cold world from which all the rivers of Midgard flow. Occasionally, he may slip into Hel to visit the dark goddess some consider his master.
Yggdrasil's Own Parasite
There are a number of parasites that live in Yggdrasil, so Nidhogg is not alone at all. There are four deer, at least seven other large snakes, an eagle that lives on top, and even a squirrel named Ratatoskr.
All the creatures that live in Yggdrasil really do damage, but Nidhogg does the most damage. He chews the roots. Scholars believe it is meant to represent the ever-present evil that eats away at the hearts and souls of men, and how one must always be vigilant in the face of evil.
But Nidhogg has another mission:
Balance is extremely important in Norse mythology, and although Nidhogg represents a fearsome force, it is important in supporting the balance of Yggdrasil.
A large eagle, which represents wisdom and virtue, perches in the upper branches of the tree, while Nidhogg, which represents chaos and evil, lurks in its roots.
The constant tension between the eagle and the dragon is fueled by Ratatoskr, a squirrel who runs up and down the tree while being insulted by both enemies. This tension may seem undesirable, but it actually promotes a cycle of growth in the tree of life. After the eagle and dragon spend the day destroying Yggdrasil in their frenzy of attacking each other, the tree is bathed in water from the Wells of Urd, which promotes healing and new growth.
Besides bringing balance to Yggdrasil, the monster also participates in the punishment of criminals. He rules the dark shores of Nadastrond, where the corpses of murderers, adulterers and oath-breakers are banished. A terrifying hall, with walls woven with snakes and a ceiling dripping with venom, awaits these criminals, and inside the hall the dragon chews on their bodies.
Finally, the dreaded dragon has a role to play in Ragnarok, the day the giants will attack the gods and destroy most of their world. Ragnarok will begin when the dragon finally manages to chew through the roots of Yggdrasil, causing the tree to turn yellow and the worlds it supports plunge into a three-year winter. At the end of this icy and chaotic period, he will fly out of the underworld, carrying dead criminals and leading the giants to attack the gods. Eventually, he will survive this battle and become the force of evil that balances good in the post-Ragnarok world.
Nidhogg in modern culture
If you're a big gamer, chances are you imagined this when you saw the word "Nidhogg":
Nidhogg lends its name to numerous video games, including World of Warcraft, Ragnarok Online, Age of Mythology, and Final Fantasy XIV. He is also Alduin's inspiration in The Elder Scrolls V: Skyrim.