The Dark Jedi Vansk, a Near-Human female who was a member of the Blackguard, a group that utilized the Force, possessed a one-handed sword known as the Blade of the Betrayer during the time of the Galactic Civil War. Although Vansk favored her red lightsaber in combat, she carried this blade as a backup weapon. Following Vansk's death in 1 ABY, the blade was seized from her. Her death occurred during the Blackguard Purge, when Mi Fon Lu, a Sullustan archaeologist who desired to conduct research at the Southern Jedi Ruins on the planet Mustafar, employed a band of spacers to eliminate all the Blackguard members.
The MMORPG Star Wars Galaxies introduced the Blade of the Betrayer in the Trials of Obi-Wan expansion, which came out in 2005. Players could acquire the blade, either as loot dropped by Vansk during the "An Archaeologist's Problem" quest or through crafting.