|Location||across many regions|
|Built||varies by world|
The Earth Seam is an Underdark channel of earthen elemental matter that flows like a river in some areas, and others like a slow-moving lava river. On the world Bal-Kriav, some believe that Benevolence used this unusual river in the making of the world around it.
Where a river runs with water, the Earth Seam is a flow of sand and rock. From collisions and constant grinding, much of this stuff is of the finest sand.
- Dalun Irak, of the Tharag - "Skree Ruvalk"
In the Demon Spawn War, the primordial lord Geb, was an ally of the Covenant. All of the earth elementals in and around the Earth Seam answered to him. His soldiers worked hard to keep the demons from using it as a means of bypassing Covenant defenses, reaching areas deep behind friendly lines. They were largely successful. Back then, unless barges were made by earth elementals, and towed by them, there was no way of traveling the river without getting pulverized to pieces.
Many have used the Earth Seam to move about the Underdark, populating distant places, some thousands of miles from where they started. One of the earliest, were gnomes in the thousands, fleeing the demons taking over Hezmort. These gnomes would become known as the Svirfneblin. After fleeing into the Krephus Sink they made for the Earth Seam and its portal. Today, these gnomes, changed by Callarduran's death, are scattered across Bal-Kriav's subterranean realm.
Others to use the Earth Seam to seek out new lands and resources was the Akthol and the Tharag. In 310 LE, they formed a joint expedition with settlers from each clan. From God Anvil Launch, they were sent along the earthen flow, knowing full well that it may carry them such a great distance that they may never see their hearths again. The expedition was taken far, hopping along Seam Portals, looking for areas to settle. A year after the expedition started, the founded Felak.
Early travel along this elemental river was done by barges. These were constructed by earth elementals, then in exchange for gems, they offered to tow and pilot their customers along the river. In the First Epoch, a Lith-Crillion research vessel came ashore near the God Anvil Launch. It was a ghost ship. It was studied at Khulbarazâr, then reverse engineered. From this came the Mhornar Skree, or Dirt Barge. They are powered by shadow magic engines. Some describe this magic as tricking the Earth Seam into thinking the vessel is Earthen, or part of the Earth Seam.
The breadth of the earthen flow is as random as any major river, and its extent unknown. One expedition spent three decades following it, along the way naming the Seam Portals they passed through or avoiding those too dangerous.
Navigation down the earth seam is rather simple, hang with a bunch of big boulders and you got it easy - unless of course they collide with a seam spire and then you got trouble. Travelling up stream is not like sailing a ship, wind does not move you through this elemental stuff, it requires shadow magic and the taming of earth elementals . These workers will then literally drag you through the stuff at a slow and somewhat safe rate - this is why Mhornar Skree have wedge sterns and aft, each strong of weld, and blessed by Danzar-Khâl. As for getting the help of earth elementals, they gladly accept metals and gems, which though they consume, are not digested since we all know they don't work like flesh and blood, its a strange custom even for their kind.
On the journey, we passed innumerable passages and crossed caverns so vast that many days passed before it narrowed back to normal. The diversity of peoples and civilizations we encountered were far beyond any of our expectations.
- Dalin-Gumil, expedition leader from Smizerak, fragment from the Lost Series - "The Long Flow"
There have been attempts to channel the Earth Seam and redirect it, but these have all ended in failure. The stuff that goes off the main flow turns solid over time. As far as using walls of force to flood areas, these spells and others are of no use. The only magic that seems to work with it is shadow magic.
In the First Epoch, the Earth Seam got more dangerous when thousands of earthen got loose of their Rilirthad masters. Most of the escapees got on the Earth Seam and spread across the Underdark.
The Earth Seam has regenerative properties to Earthen. It is because of this that many earth archons and earth elementals make their home in and around it.
When Geb became a lesser power, he acquired the ability to create earth seams. This was to counter the fiery machinations of Surtur and his great lava rivers (c.f. Great Vein of Surtur).
The Earth Seam has entry and exit points called Seam Portals. Passing through one can take you to far away places. Before the Second Epoch, going the reverse - back through these portal was impossible for anything other than an Earthen. This changed with the advent of specialized Mhornar Skree called Nalgu Skree. This ship type, very expensive to build and operate, can pass through Seam Portals in either direction.