The Sea of Eden is actually a section of the Korias ocean that has been made particularly suitable for life.
At its center is the Hive and the Godspire. Surrounding that, however, are the seamats, Coral Reefs, and Sea Cliffs that Harkon Armal made for the Mazunti to live upon. Deep below the surface volcanic vents, created by Davos on Culthet. On the edge of this sea are the Black Coral Gardens, and then the largely empty ocean proper.
The Hive, The Godspire