Seax (also sax, sæx, sex, latinized sachsum) is an Old English word for "knife".On Nilfeheim, the term seax is used specifically for a type of dagger typical of the Neo Vikings and isvirtually the same as the ones used by the peoples of the Migration period and the Early Middle Ages, especially the Saxons, whose tribal name derives from the weapon.(on Earth)
Every man on Nilfeheim, even the Low Men carry a Seax. Eric Olafson made the knife famous beyond Nilfeheim as he carried at least one almost everywhere and used it frequently.
In heraldry, the seax is a charge consisting of a curved sword with a notched blade, appearing, for example, in the coats of arms of the Mortensen clan (Nilfeheim)
Old English seax, sax and Old Frisian sax are identical with Old Saxon and Old High German saks, all from a Common Germanic *sahsom from a root *sah, *sag- "to cut" (also in saw, from a PIE root *sek-). The term scramaseax, scramsax lit. "wounding-knife" is sometimes used for disambiguation, even though it is not attested in Old English, but taken from an occurrence of scramasaxi in Gregory of Tours' History of the Franks.
The name of the roofer's tool, the zax, is a development from this word.