The player must go through this area to get to Celestinine Mountain. In order to do so, the player must put Crustles to sleep with a powder vial and move them into holes. That done, the player may hop on them in order to progress through the area.
Places of interest
In the south of Route 2 you’ll be in a small area with Fiore Mansion, where Amaria and Titania live. It also contains the sixteenth gym in Reborn.
After getting the powder vial in Agate Circus, interact with the small cave nest outside for a Crustle to appear. They appear indefinitely, but only one Crustle can spawn per nest. You can put them to sleep with a sleep powder vial to use them for the puzzle.
You Stepped Into The Wrong Territory
After activating HM Surf, you must complete the northern Crustle Puzzle to have a path to Celestine Cascade without jumping on shaky rocks (Or else the powder will spill). After that, get a rage powder from the red trees and go through Celestinine Mountain to get to Celestinine Cascade. Use the rage powder vial to wake up the Crustle in front of a small cave to make it leave. Inside you can see a cave nest. Interact with it while having a PokeSnax to have a Salandit to appear. They will spawn indefinitely, but only if you still have some PokeSnax with you (one will be consumed each time they spawn). Alternatively, you can use Rock Climb to get rage powder west of the cave, but you won’t get Rock Climb until later in the game.