The Sea Subterranean
Location: Pandemonium / Phlegethon
HEARSAY: A vast, underground ocean, stretching out to almost-fill one of the largest caverns of Pandemonium, lies somewhere in the mad tunnels of Phlegethon. Unbound by conventional gravity, the dark waters instead move towards the closest surface, which creates a weird situation where there’s water both below you and above you, with an air bubble in the middle. In the air bubble there is, of course, a perpetual storm raging, whipping the water up into peaks, waves and whirlpools. Deep beneath the surface is rumoured to be great treasure, guarded by hideous, misshapen beasts.
DESCRIPTION: The rumours are true, on the third layer of Phlegethon does indeed lie a huge underground sea. It’s would be a strange phenomenon to the residents of the plane, but of course they don’t care much about anything but themselves. To clueless primes that are too used to their own mundane oceans with normal gravity, the Sea Subterranean is a strange sight indeed. It begins with a trickle, sliding around the walls of the more narrow tunnels. A body continues until they’re up to their knees and there’s a good foot of water on all sides of the tunnel—and then as the tunnel opens up into a colossal cavern, only then do they see the whole sodding thing. It’s not known how large the cavern would be if it were empty, but the water is said to be a couple of miles deep and the bottom. And the top, of course.
The storm-bubble at the centre is thirty miles long and ten wide, making the so-called ‘sea’ perhaps more of a lake. It’s hard enough for cutters to understand the tricky surface-oriented gravity of Pandemonium, and land lubbers never really do stop gaping at it.
A blood calling himself Captain Vagrish (prime human fighter [he/him] / CN; madness: perfectionist), formerly of Toril, called “the Mad Captain” by those who know him, sails the Sea Subterranean. He operates out of the burg called Ship of Fools, and hopes to seize the cargo of any other ships that would sail upon it. The fact that there aren’t any cargo ships sailing on the Sea Subterranean does not seem to deter his enthusiasm. He wears an eye patch over one eye, although there is an eye painted onto the patch, which gives the cutter a disconcerting look to say the least.
Deep beneath the swirling waves lives a tribe of reclusive aquatic elves devoted to Deep Sashelas, the elven power of the ocean. They’re led by Aquis Webtoe (planar sea elf priest of Deep Sashelas [he/him] / CN; madness: can’t stay still). So far, they haven’t much objected to the Mad Captain’s plans for the Sea Subterranean, so they’ve left him to his barmy work.
SPECIAL FEATURES: The Sea Subterranean is disorienting to look at and confusing to pilot a vessel on, considering that it takes the odd gravity of Pandemonium to its logical limit. Anyone swimming through the waters must pass a Wisdom check to make sure that they’ve retained their bearings in a confusing world. Failure indicates that a berk starts travelling in another, random direction without realising it. The Sea Elves and those that are familiar with these waters do not need to check.
Source: Dave King and Jon Winter-Holt. This location is homebrew, but inspired by real world mythology about underground oceans.