In addition to being a Tear Jerker, Drachma's story of the death of his son and his crew include watching his son fall to his death and hearing him scream all the way down. It's no wonder that Jack's grisly death still haunts Drachma years later.
Mind Stealers. Some sort of giant bug riding on/controlling a human/corpse. Where do you find them? The catacombs beneath Valua's Lower City.
The Squid's Nest Discovery is unsettling due to 1) being an even bigger squid than the already ginormous squid you can encounter and 2) It's perfectly capable of snatching entire ships out of the air!
There's just something...unsettling about a Looper ten times the size of your ship.
Elcian, who appears in the Dark Rift after defeating Galcian aboard the Hydra for reasons unknown. A black Looper that utterly dwarfs the Delphinus in size and all it does is sit there and not move an inch. You can fly right up to its face and it won't engage you unless you do so yourself.
The Dark Rift, an Eldritch Location if there ever was one. Incredibly difficult to navigate, dark, quiet, littered with shipwrecks, some of the strangest scenery and eeriest music in the game, and the fact that it wraps around the entire planet, effectively cutting the world in half, makes for a really unsettling atmosphere. It's heavily implied that the Dark Rift is connected to a lost Black Moon, but the exact details are left to the player's imagination. Even better: when the skies are calmed when Soltis reemerges (meaning all the normal rifts and any cyclones dissipate), the Dark Rift is still there.
The Vortex. Similar to the Dark Rift, it's dark and quiet. Unlike the Dark Rift, it is completely empty. There is no strange scenery or wildlife to encounter, and there is a massive thunderstorm raging just outside the Vortex, illuminating the ruins of Soltis with every flash of lightning. And this is the safe path to the surface, anywhere outside the vortex the atmospheric pressure is so strong that it would crush any ordinary ship. It doesn't get any better when you reach the bottom.
Bleigock: the boss living underneath the coliseum. He's surrounded by the defeated and grown fat on the bodies of the dead, or possibly, the injured people thrown from above. To make matters worse its stomach is see-through allowing you to see its partially digested meals...
