Sejan cave

Sejan cave (not to be confused with Sejan beach cave) is located in the middle of the eastern side of Sejan's central mountain range. It's a dark, maze-like place that's easy to get lost in, not to mention a dark secret lurking within.

Venturing in alone
The cave can be discovered on player's own. Without a torch, the player can't explore the place much. Even with a torch, they are soon stopped by a deep drop that can be climbed down only with a rope. This rope stays in the cave and can be climbed down on any further visit. In the lower chamber, players can attempt to explore the surrounding tunnels, but can't find anything. This is to be expanded upon, with leftover code containing players stumbling upon a large stash of Krats.

Shyni's adventure
There's another time the player gets to explore the cave. After gathering necessary things for Shyni, the two set off for the cave, armed with a stone tablet that has a map of the caves on it. Following the directions, they find a room with an innocent-looking bowl on a piedestal. Touching it causes the affected person to briefly turn insane and want to kill or otherwise violate anyone in vicinity. Things can go in either direction, ranging from both the player and Shyni uninjured and only slightly frightened to one of the participants ending up murdered.