Kappisverðr

Kappisverðr, also known as Helidswert (or Haliþswerd in older script), Hero's Sword, and Blade of the Champion, is a legendary sword located by Berg Firstcomer millenias ago and wielded by him during his lifetime.

It is assumed to be a craftwork of the Missing People, a nation that left behind settlements and artifacts, sharing ancestry with many other artifacts, like Ísbrjótar.