Rarities

The fourth layer is not a comfortable place to be for most Tatsukoi. It is a dark, damp place with winding tunnels and steep caverns.
Those who don’t know where they’re going can easily get lost in the twisting tunnels causing many to never make it out of this layer. Some eventually find their way out, but they are often changed by the experience. The overwhelming isolation of this layer is difficult to handle, and causes many to lose their minds.

This layer usually causes Tatsukoi to develop traits to help them navigate through the tunnels, typically by enhancing one of their senses in some way.