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That eagle thinks he's all that. Well, my new insult will be so scathing, he'll molt his feathers! Now all I have to do is think it up.

–Nidhogg to Mallory Keen in 9 from the Nine Worlds.

Nidhogg (also spelled Níðhöggr or Níðhǫggr) is a great dragon-like serpent who lives at the roots of Yggdrasil, the World Tree. He is always chewing on the roots of the world tree, attempting to destroy it. He is mortal enemies with the unnamed eagle that lives at the top of the Tree, as Ratatosk the Squirrel continually feeds both of them insults from each other.


Nidhogg is green and brown, with a roughly lizard-like shape and a long tail. He has glowing yellow eyes and two sets of razor-sharp fangs. He sits coiled around the root of Yggdrasil that extends into Niflheim.

Magnus Chase and the Gods of Asgard

The Sword of Summer

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.

9 from the Nine Worlds

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 so 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 hear Keen's one-liners so he won't eat her, and 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.



  • Many times, 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.
Magnus Chase and the Gods of Asgard
Core Series: The Sword of Summer | The Hammer of Thor | The Ship of the Dead
Main Characters: Magnus Chase | Alex Fierro | Blitzen | Halfborn Gunderson | Hearthstone | Loki | Mallory Keen | Samirah al-Abbas | Sumarbrander | Thomas Jefferson Jr.
Secondary Characters: Randolph Chase | Gunilla | Natalie Chase | Amir Fadlan | Alderman
Minor Characters: Annabeth Chase | Frederick Chase | Helgi | Hunding | Vala | Junior | Lars Alhstrom | Stanley | Inge | Percy Jackson | Stan | Alviss | Miles | Wildflower | Sunspot | John Henry
Norse Gods: Freya | Thor | Balder | Ullr | Frey | Odin | Heimdall | Vidar | Sif | Frigg | Tyr
Minor Gods: Skírnir | Mimir | Ran | Hod | Hel | Sigyn | Aegir | Nine Billow Maidens | Njord | Kvasir | Holler | Forseti | Glum | Lofn | Sól | Idunn
Jotnar: Surt | Gerd | Norns | Utgard-Loki | Harald | Ymir | Geirrod | Gjalp | Greip | Thrym | Thrynga | Tiny | Little Billy | Hrungnir | Red | Tattoo | Gunlod | Suttung | Baugi | Skadi | Hrym | Eggther | Norns
Monsters: Jormungand | Ratatosk | Vedrfolnir | Nidhogg | Fenris Wolf | Lindworm | Wight | Brunnmigi | Siersgrunnr | Garm
Magical Creatures: Dwarf | Elf | Sleipnir | Stanley | Marvin | Otis | Hulder | Nøkks | Vatnavaettir | Nisser | Troll | Raven | Hugin and Munin
Related Content: Rick Riordan | Hotel Valhalla Guide to the Norse Worlds | 9 from the Nine Worlds | Magnus Chase and the Gods of Asgard (Films)