Is just an idea I had. Kinda functions like a skull fort but it requires to be observant instead of combat provess.
Unlike the skull fort it appears in red sea zone. The way to find it is by star navigation. Basically the "skull" or mark in the sky can only be seen at night time. And the Safe route to the isle is only up at night. It could be a constellation of a mermaid holding a lantern.
(There would be a safe zone near the island so you can park)
Once you get there you have to figure out riddles on the walls, kinda like gold hoarder maps, to find the key to the vault.
And if you open the vault the island begins to sink, when it's gone the safe passage is also gone leaving you in red sea territory.
Making a hasty retreat needed.
I think this kinda addition would make for fun interesting gameplay. And the island could be a random piece of terrain so it doesn't have to be in the exact same places.
