Throughout the sea, vast spires of stone and coral rise up from the bottom of the ocean—in some cases, over a mile in height. Some reach the surface, while other clusters lie hundreds of feet below it. While these spires formed naturally, they’re often interspersed with a more dangerous—and unnatural—substance. Demonglass is similar to obsidian, but virtually indestructible. These demonglass spires—commonly called “needle teeth”—can pierce the hull of a swiftly moving ship despite being just a few inches in width. The spires in this region were created by the Lurker in Shadow during the First War (though it wasn’t responsible for the demonglass found elsewhere in Eberron, such as Ashtakala in the Demon Wastes).
The region known as Shargon’s Teeth— a Common adaptation of the Sahuagin name for the Devourer—lies directly between Sharn and Stormreach, and is the most infamous manifestation of these hazardous needle teeth. Stone spires and demonglass spikes of all sizes are scattered between this chain of islands. Only the most seasoned navigators can plot a course through the Teeth without the help of a sahuagin guide; as a result, the islands have long been a haven for smugglers and pirates, preying on ships that founder on the Teeth.
Throughout the Thunder Sea, needle teeth are a dangerous hazard for those who stray from the established trade routes— but they also provide an opportunity to interact with creatures of the sea. Any number of aquatic monstrosities may make a lair in the upper reaches of a spire. The sahuagin also often colonize the larger teeth, carving tunnels throughout a spire. High teeth thus serve as outposts projecting up to the upper waters where light can reach, allowing travelers to visit a sahuagin outpost without having to descend to the absolute depths.