|0148 (FC Dungeon rooms)
0149 (Dungeon Glitch room without event)
0150 (Monochrome room)
0157 (Dungeon Glitch room with event)
This area consists of many rooms, creating a labyrinthine layout that may get Madotsuki lost. The area is constantly dark, which requires the Lamp effect to brighten. The designs of each room may change between a set of red faces or a set of purple faces, alongside a completely monochrome room leading to the White Desert Underground Lagoon. Some Lizardmen can be found throughout the dungeon, one of which stands in front of a statue.
A rectangular room within the dungeon has an event associated with it known as the Famicom Glitch event. Every time Madotsuki goes to sleep, there is a 1/3 chance that the room's upper-left corner can be interacted with to make an empty text box appear. Continuing to interact with the wall will simply prompt the same empty text box, though the graphics will slowly become jumbled and distorted. After interacting enough times, the dungeon room will become fully corrupted and a shrill corruption noise will play as Madotsuki wakes up from her dream.
- In all previous versions, the room containing the Famicom Glitch event was unlit like the rest of the FC Dungeon's rooms, requiring the Lamp effect to light up the room.
- Strangely, the FC Dungeon's map size was increased from 130x130 tiles to 150x150 tiles in version 0.10, although no new rooms or changes were made to the area alongside this expansion. This was likely due to the game being remade on a new instance for 0.10.