ideas

Ascalon, the spear that St. George used to kill the dragon

Gram, the sword that Odin struck into the Branstock tree which only Sigmund the Völsung was able to pull out. It broke in battle with Odin but was later reforged by Sigmund's son Sigurd and used it to slay the dragon Fafnir. After being reforged, it could cleave an anvil in half.

So maybe something incoporating those names, or the names of something else used to kill dragons.