Nidhogg and Ratatosk
The first world to be created in Norse mythology was Muspelheim, the world of volcanic fire. The next world that came into being was Niflheim, the land of ice and cold and, where it meets the world of fire, a world of mists. Between the two realms of fire and ice grows the World Tree, Yggdrasill, with the rest of creation, the worlds of Gods, men, elves and giants in its branches. One of the roots of Yggdrasill draws sustenance from the spring at Hvergelmir, located in Niflheim. Under this root, one of three that support and nourish the World Tree, lies the Dragon Nidhogg (Malice Striker) who, along with the Dragons Goin and Moin, gnaw on the main root while the Dragons Graback, Grafvolluth, Svafnir and Ofnir chew away at the twigs that grow on the tree. Even though the three Norns repair the damage every evening, Nidhogg will eventually gnaw through the root and Yggdrasill will topple, ushering in the end to all the worlds and the final battle: Ragnarok.
High in the branches of Yggdrasill perches a giant eagle in whom is housed the knowledge of all the worlds. The eagle abhors Nidhogg and his destruction of the World Tree. Using the squirrel, Ratatosk, as a go-between he and the dragon trade insults up and down the height of the tree, much to the delight of the quarrel-loving Nidhogg and the gossip, Ratatosk.
Niflheim is also the abode of Hel, daughter of Loki, and mistress of the unvaliant dead. Heroes and those who die in battle spend the afterlife in Valhalla feasting, drinking and telling tales of valor; those who live forgotten lives, who have no warrior traits and who died of disease, suicide or accident are sent to the Realm of Hel where they work, cold and miserable. The wickedest of these miserable shades are sent to Nidhogg, where their souls are sucked from them for his nourishment.After the final battle Nidhogg will fly over the battlefield eating the souls of Fire Demon, Rime Giant and God indiscriminately until he, too, is killed by Surtur the Fire Demon.