Gleipnir

In the Prime Universe, Gleipnir was the magical chain with which Fenrir was bound. It lost part of its potency as the power of the old gods waned, allowing Fenrir to briefly escape at will, but the magic of the fetters would always eventually drag him back. (PROSE: The Winter Quests)

Concepts from Norse Mythology in Jenny Everywhere media
Individuals Fenrir • Frey • Freyja • Hel • Jormungandir • Logi • Loki • Nari • Odin • Sigyn • Sleipnir • Thor • Wyrm of Loki Species & Classes of Beings Aesir • Elves • Norns • Trolls • Valkyries • Vanir • Winged horses Locations Alfheim • Asgard • Valhalla Events Ragnarök Media Grímnismál • Ride of the Valkyries