Terethia, or Old Terethia, was an ancient and powerful Fae kingdom, which rose to its zenith during the Terethian Era. The Guenvae of Terethia were unparallelled sorcerers.
They were rumored to have gained secret knowledge from the Vorgar Lords during the Godstrife Era. After the Vorgar Lords were defeated, the Terethians continued to advance in magical sciences until they suddenly disappeared. Texts recovered from the ruins of Old Terethia revealed the Elves' obsession with a growing dread within Tarn.