There are several evolutionary items you’ll need to find to evolve your Pokemon. Reaper Cloth is one of the Evolutionary Held Items found in Pokemon Brilliant Diamond and Shining Pearl (BDSP). The Reaper Cloth is an item which when held can cause the Pokemon Dusclops to evolve into Dusknoir when traded. This walkthrough will show you where to look for a Reaper Cloth in Pokémon Brilliant Diamond and Shining Pearl.
There are two known and easily available locations you can find the Reaper Cloth in Pokémon Brilliant Diamond and Shining Pearl.
Route 229 (Battle Island)
The Reaper Cloth can be found North of the Resort Area on Route 229 in the Battle Area. The Resort Area is only a post-game area, and you need to become Champion by defeating the Elite Four to unlock it. Head north on Route 229 until you find a small rock to your east. There you will find a tree that you can cut using a hidden “CUT” move. Continuing, you will find a Reaper Cloth lying on the ground.
Battle Park
You can buy a Reaper Cloth in the Battle Park Exchange Service or 5 BP. The Battle Tower unlocks after you’ve defeated all eight of the Gym Leaders, and you want to test your skills against some of the harder portions of the game.