The Shattered Sea
Long before any of the ‘free-willed’ races roamed the land, the Firstborn were masters of the natural world. They are very like the animals they represent, only the most-perfect embodiment of the aspects of these creatures.
The Firstborn were the leaders and protectors of all natural life and long defended the wild areas from incursion by the civilized kind. Slowly but surely, man and the other ‘free-willed’ pressed the areas protected by the Firstborn until only the mainland of the Hesperean sea and the lands beyond were their domain.
This too may have passed. The last Keeper was recently brought down by an assault of tieflings, and although she survived her power to preserve the mainland may have waned. Only time will tell if the era of the Firstborn is gone forever from this world.