|“||It's a mystery to me why we put up with this behavior. I mean, can't someone slip him a chew toy?||”|
–Hunding in Hotel Valhalla Guide to the Norse Worlds
Nidhogg (also spelled Níðhöggr or Níðhǫggr) is a Dragon who lives at the roots of the world tree, Yggdrasil. He is always chewing on the roots of the world tree trying to kill it. Ratatosk constantly delivers insults to him to try and destroy the tree faster than Vedrfolnir and the unnamed eagle on top.
Although he does not physically appear, Blitzen mentions Nidhogg to Magnus Chase after they were chased out of Yggdrasil by Ratatosk. He says Nidhogg and the eagle are kept in a frenzy due to the insults, lies, rumours, and nasty gossip about each other from Ratatosk. Magnus thinks that's crazy as they all live in the tree, including the squirrel, but Blitz says people have destructive impulses and some of us want to see the world in ruins just for the fun of it.
So’s Your Face!
After she accidentally stumbles into Niflheim, Mallory Keen follows Thor to Hvergelmir and meets Nidhogg coiled around the base of Yggdrasil, he apparently gnaws on humans too due to the bones Keen stepped on. Nidhogg is busy thinking up a new insult for the eagle in Yggdrasil's treetops, Keen gets the idea of helping him with that in exchange for helping her climb the world tree. Upon noticing the einherjar, Nidhogg was confused at first then prepared to attack, but he got hurt when Keen said that Thor's butt had louder roars. He was impressed by her knives and even sharper tongue, he actually agrees that his brain is emptier of insults than Odin's left eye socket. Nidhogg agrees to here Keen's one-liners so he won't eat her, they even shake hands.
Mallory Keen starts off with the four classic retorts: I know you are, but what am I?, I’m rubber, you’re glue—whatever you say bounces off me and sticks to you., Takes one to know one. and So's your face!, Nidhogg at first pressed his ear to her mouth to listen carefully. Then they test it out on each other, starting with Keen calling him an ugly snake. After getting the hang of it, Nidhogg gets hungry and asked her for dinner, but Keen had to get back to Hotel Valhalla.
Hunding has described Nidhogg's appearance as snaky, with sharp teeth and an irritated expression.
Nidhogg's tail looked like a branch of Yggdrasil, it was brown and green like the rest of his body but unlike the other roots it looked scaly. He had claws on his powerful back legs and huge yellow eyes.
- Sometimes, Nidhogg is depicted as a serpent.
- Nidhogg's name means “Curse-striker” or “He Who Strikes with Malice”.
- It is said that after Ragnarok, Nidhogg will emerge carrying the corpse of a Jotunn.