The Hyperboreans were a race of tall, gaunt, sorcery using men who occupied Hyperborea, in the northeast of Hyboria, seen in Robert E. Howards fictional world of Conan: The Barbarian.
In Age of Conan: Hyborian Adventures, the player comes across the Hyperboreans in parts of Cimmeria, specifically the Eiglophian Mountains and Atzel's Approach.