Fantasy Location: The Hidden Island
The Hidden Island is normally avoided by ships. It lays in the deep sea, surrounded by a pod of kraken. The island itself has two buildings on it. Both are submerged just a few feet under the water, so are a bit of a navigation hazard, especially during storms.
The two buildings are ancient temples. Each has a sundial inside centered inside. If someone moves one of the dials, they will hear a rumbling sound.
One dial actually raises the island out of the sea. Once it’s out of the water, it instantly starts growing plant life. Within six to eight hours the island is fully revegetated like it was never underwater. Once the island is out of the water, the second sun dial opens a previously hidden door. This dial does nothing if the island is still under water.
This opens into a Dwarven Village which has a secret passage down into the Underdark. The Dwarven city is unnamed and empty.
From the Dwarven City passages in the Underdark eventually lead to a drow city of 3000. It sits upon an huge underground sea. If someone manages to get to the middle of the sea, there is a huge whirlpool that goes upwards to the ocean. Entering the whirlpool takes someone to the ocean surface. During storms the whirlpool reverses and instead sucks objects from the sea above down in to the caverns.
Underdark Frontier Encounter List
Possible list of encounters in the Frontier areas of the Underdark. Frontier areas are lightly settled tunnels or caves, but communities are small and far apart, usually separated by miles of tunnels. Occasional larger forts maybe present to give warning to larger settlements in the distance.
Bugbear band (hunters, scouts, family group)
Dragon, juvenile deep
Dragon, juvenile copper
Dragon, young adult black
Dragon, young red
Duergar marauders, scouts, hunting party, miners
Goblin war party
Hound of the gloom
Ooze, black pudding
Scorpion, giant whip
Spider, Large monstrous
Spider, giant sun
Spider, giant whip
Swarm, swamp strider (near lakes, rivers, and other wet/swampy areas)
Troglodyte war party
Underdark: Settled Area Encounters
Settled Underdark areas would be a large cavern with a city or several small villages. It could be on the edge of a larger city or fortress and maybe heavily patrolled. Most likely the lesser creatures and undead will be Illithid or Drow slave parties, sometimes accompanied by one or two of that race to control them.
Centipede, Large monstrous
Dragon, juvenile black
Dragon, young deep
Illithid (Mind Flayers)
Spawn of Kyuss
Spider, Large monstrous