Draindark Scuttle

1. The Draindark Scuttle is a huge cavern just below sea level, underneath an island. There is an opening on the island one can climb down, but it gets its name from the massive drain leading to it from the sea. It has a perpetual whirlpool fed by major ocean currents that is liable to suck in any passing ship which gets too close. In its depths, countless shipwrecks from millenia of unfortunate sailors catch in crevices and on jumbles of flotsam as millions of gallons of seawater drain away into the uncharted depths of the underdark.
2. The Scuttle has changed hands a few time over the millenia. In ancient times, sirens would call to passing ships and lead them into its maw. It has been claimed at various times by kingdoms of merfolk, tritons, sahuagin, aboleths, and even pirate lords from the humanoid races. Currently, a ragtag clan of sahuagin bandits is using it for a hideout.
3. One word: salvage. Though the Draindark Scuttle is extremely dangerous, it lies right on a major tradewind and oceanic current, which brings no shortage of traffic in its vicinity. Though experienced sailors know to avoid it, all it takes is a foggy day, a nasty storm, or bad charts to end up past the point of no return. As a result, it's a veritable treasure trove of lost cargo and rare artifacts. Whoever claims the cavern has access to the provisions of the lost ships for food and rum, as well as royal treasure ships, fine lumber (once you dry it out) and all manner of other goods that could conceivably survive a bit of water damage. A ship careened on the island will find plenty of timber and barrels of pitch for patches. The sahuagin currently residing there are little more than predatory marauders, but previous occupants have been able to build a strong economy around the riches found there.
4. It's easy to be lured in by thoughts of wealth and supplies to be found. But the current occupants are not keen to share. If one arrives the hard way (by the whirlpool) then the challenge is fighting off murderous shark-people while battered, wounded, and half-drowned. The terrain lends itself to vicious underwater combat in dark conditions with blind corners and tight spaces galore. There's so much junk that a diver can't see farther than 10-15 feet in any direction. Lots of cover and hiding spots.
5. As mentioned in #3, there's lots of treasure to be found if one is willing to brave the dangers. Maybe there's a lost imperial treasure ship with chests full of gold! Maybe an unlucky prince went down with his ship AND his prized magic sword!
6. It's right on a major shipping lane. Most captains deliberately circle wide, never actually coming within sight of the island. But it's right there, and a captain could take them there for the right price. Or if they're unlucky, they'll get there without meaning to and MAYBE survive the Drain. https://dungeonmasterblock.freeforums.net/thread/2371/dm-nastics-154-moving-mountains

Type

Cave