The Darksome Nightmare

Unlock Criteria: Have a Pokémon Brilliant Diamond & Shining Pearl save and complete the game

Description: Get more details from Cael of the Pearl Clan about the terrifying Pokémon he saw and find out its location so you can survey it.

When given this request, Cael will appear and tell you of strange goings on in the Clamberclaw Cliffs. Go there at night and Darkrai will surprise you and challenge you to a battle