Elder twin son of Wærxæg; valor-eponym ("courage" in Ossetian). Killed by his twin brother Akhsartæg in the foundational misidentification-tragedy of the Nart cosmogony: pursuing a magical white deer to the underwater realm of Donbettyr, the twins encountered Dzerassae (Donbettyr's daughter); a series of jealousy-and-misunderstanding episodes culminated in Akhsartæg discovering Akhsar's sword next to Dzerassae and inferring betrayal, killing his brother before realizing the misidentification. Died childless; his line does not continue, making the Nart-genealogical core proceed through Akhsartæg + Dzerassae alone. The Iranic valor-root *xšaθra- in his name preserves the Vedic ksatra warrior-class etymology, marking him as the eponym for heroic-warrior-power within the Nart frame. The twin-misidentification-fratricide narrative is structurally parallel to but independent of similar Indo-European twin-tragedies (Romulus-Remus; Cain-Abel through Hebrew transmission).