—Semirhage on the ignorant girls of the White Tower
Dueling blades were used in a game called sha'je, a violent dueling contest popular during the Collapse, when the Dark One's influence awakened the darker side of human nature and caused society to degenerate. The participants used twin blades, the right called aran'gar, the left named osan'gar. In the years immediately preceding the final collapse into war, murder, rape, and even torture became regular parts of many spectator sports. This game was particularly vicious, as both blades were coated with a slow poison, so that even the victor seldom survived. Because of this fact, the game is thought to have been started or perpetuated by Friends of the Dark.
Although the dueling form did not survive the Breaking of the World, the names live on in two Forsaken reincarnated by the Dark One: Aran'gar and Osan'gar. This marked the first time the Great Lord would name his tools himself. It is likely these names were chosen because of the right and left handed meanings. Both of these agents would eventually infiltrate the scattered forces of the Light; the Dragon Reborn's Black Tower and Egwene al'Vere's Rebel Hall of the Tower. Like the slow poison, they would seem to aid the two factions, while slowly leading them to destruction.