When the Phantom Thieves enter a different area of Mementos, there is a small chance it will be a Deviation. Areas that are Deviations will be noticeably different in some way from other areas of Mementos. There are a variety of different types of changes that can occur when entering a Deviation, and these changes can be either negative or positive. Up to two types of changes can be in effect in a Deviation area at the same time, however, it is impossible for both changes to be beneficial to the group; at least one change must be negative.
The possible changes are as follows:
- The area is pitch-black, limiting the player's vision, and the mini-map is also inaccessible
- Only strong Shadows can spawn
- A large amount of Shadows will spawn
- The Reaper appears at the beginning
- There is a pitfall
- Disaster Shadows appear in large quantities
- A large number of search objects are dropped
- Many flowers will spawn
- Many treasure chests will spawn
- Simplified map layout
Leaving the Deviation area will cause it to reset and become a normal floor.