| Category | Oceans |
| Region | Phangul |
| Map | Olvagny |
The Heliotrope Sea, named for its distinctive purple hue, is situated in the subterranean region of Phangul. Its color is derived from the Tears of Achamâz, a gemstone that bleeds into the surrounding waters. These "holy blocks" of Tears of Achamâz are transported via large barges to Phure-Zil, and then to the surface, destined for the grand citadels of the Lands of Purity. In addition to this sacred cargo, the Heliotrope Sea serves as the heart of the Gnemdos Trade Network, facilitating the passage of a vast array of commercial goods. The core trade routes of this network extend outward in all directions, with the ports of Snahyrull, Dienkigec, Phure-Zil, and the river town of Gnemdos serving as critical nodes.
The northern sea is nourished by the Belevorn River. Observed from above, thousands of feet upward, this sea receives the cascades of three immense waterfalls and numerous smaller ones. The journey commences on the forest floor of Pellangoth, where three colossal openings exist, large enough to accommodate the flight of a dragon with its wings fully extended.
The expansive Nedullu River flows southwestward, serving as the principal outlet of the Heliotrope. This waterway conveys travelers all the way to the distant Ebonmurk, another Underdark sea situated hundreds of miles to the south. The Gaereaus traverse this formidable journey aboard massive, steam-powered barges, transporting their wares to the markets of both Underdark and surface civilizations.
Around the volcano Vuzara's Oven, several pirate encampments can be found. The majority of these are Theegans, bolstered by the Witch Horde.