| Category | Oceanic |
| Location | Pearl Sea |
| Map | Ferrigaer |
Tyelcirion is a deep canyon of the Pearl Sea's hadal zone. This region plunges nearly 40,000 feet. The area teems with geothermal activity, including underwater vents and several growing volcanoes. Some of these volcanic features lie perilously close to the surface, posing hazards to ships when steam blasts across a wide expanse or massive rocks and lava flows breach the surface. While the dangers above are formidable, the underwater environment resembles an Eden, teeming with vast schools of fish that can obscure the depths in shadow. Away from the lava streams and chemical-laden vents, towering kelp forests and expansive vegetation create an underwater realm akin to a terrestrial forest.
In the Durkoth Descent (995 HE - 1355 HE), around 1150 HE, Durkoth started arriving in this region. They were those who had mutated into a more aquatic form. Most of them had once resided in Nagdúrzol. Over the following decade, they initiated the subjugation of the area's Merfolk. For two centuries, ending with the onset of Thyrms Breath, these merfolk were under Durkoth overlordship. It was a harsh period, with children separated at birth and raised in a crèche for a specific task. The merfolk of Tyelcirion bear the scars of this era. They are chaotic, destructive, and possess an evil nature, described as "equal to the sahuagin in their viciousness."