I didn't expect this thread, of all things, to be one revived after Dawntrail. And I certainly didn't expect to be the one doing it. But here we are.

There's a quest that seems to get conspicuously close to this one; It Belongs In A Museum, the quest for one of the new expert dungeons, Tender Valley. There's a tail end where we look into an old legend potentially relating to the dungeon; the relevant line is here. (Still spoilered for being soon after the expansion)

Quote Originally Posted by Teller
The devout who held vigil of the temple held this belief: “When the great serpent doth awaken, its coil shall envelop the world.” In other words, the creature's discovery was itself a pretext to legitimize their territorial expansion north.


Now, this isn't the same, but there definitely seem to be similarities in imagery and language, so we can plausibly say that it's from the same culture; either a different story about the same figure, or perhaps a later part of the same prophecy; if so, we at least have a plausible argument that the Golden Dhyata was from Tural, although I'd be hesitant to associate it to any civilization in particular.

And if that prophecy is indeed connected to the Tender Valley dungeon, then we probably also know exactly which serpent that the myth(s) refer to.

Scree.