The Crystal Pool is a location exclusive to the Kitakami region. It is located at the summit of Oni Mountain and is the area's source of Terastallization, similar to how Area Zero is Paldea's source for Terastrallization.
Trivia[]
Once the player catches Terapagos and arrives at a certain location near the Crystal Pool, a thick fog will cover the area and Professor TuroV or Professor SadaS will appear. She/He will then offer them the ScarletS/VioletV Book for Briar’s Book. After trading, a different title screen will appear with new music.