The phrase is also popular in modern gaming and fiction to describe "illegal" or overpowered weapons:

: Compared to typical iron or pattern-welded blades of the Viking Age, Ulfberht swords were incredibly strong, flexible, and sharp, allowing them to slice through mail armor without shattering.

: Each authentic blade is marked with the name "+VLFBERHT+" in a specific arrangement of crosses, which functioned like a high-end brand name in the 9th to 11th centuries. Other "Swords That Shouldn't Exist"

The phrase "The Sword That Shouldn't Exist" often refers to the legendary , a group of roughly 170 medieval Viking swords found in Europe. These weapons are considered historical anomalies because:

: They were crafted using crucible steel , a high-purity metal with a carbon content so high that the technology to create it wasn't thought to exist in Europe until the Industrial Revolution.

: It has been used to describe Sephiroth's Masamune in various media, highlighting its supernatural length and power.