Gleipnir is the rope that used to bind Fenris Wolf.

The Norse Gods commissioned the dwarves to forge a chain that was impossible to break. The dwarves fashioned the chain out of six supposedly impossible things:

  • The sound of a cat's footfall
  • The beard of a woman
  • The roots of a mountain
  • The sinews of a bear
  • The breath of a fish
  • The spittle of a bird

Magnus Chase and the Gods of Asgard

The Sword of Summer

Gleipnir's hold on Fenrir had weakened to the point where the Wolf was almost free. Magnus Chase managed to replace Gleipnir with a new rope after it was cut by his own sword Sumarbrander.