One of the most elusive Pokemon in Brilliant Diamond and Shining Pearl is Spiritomb, a ghost/dark type tied to the mysterious Hallowed Tower on Route 209. Unlike other wild Pokemon, you can only encounter Spiritomb after obtaining the Odd Keystone and completing certain steps in the game. Here's a rundown on how to complete these steps and catch Spiritomb.
How to get Spiritomb
1. Obtain the Odd Keystone
The key -- pardon the pun -- to catching Spiritomb is the Odd Keystone, a mysterious item that slots into the Hallowed Tower on Route 209. There are only several of these in the game, the first of which you'll receive from the black belt standing near the honey tree on Route 208. The black belt is in the lower corner of the route, partially obscured by trees, making it easy to overlook him.
2. Insert the Odd Keystone into the Hallowed Tower
After you've obtained the Odd Keystone, interact with the Hallowed Tower on Route 209 and insert the item when prompted. Nothing will appear to happen initially, but this is where you'll encounter Spiritomb after completing the next step.
3. Speak to 32 unique characters in the Grand Underground
Once you've inserted the Odd Keystone in the Hallowed tower, head to the Grand Underground and interact with 32 unique characters. These can be either named non-playable characters (excluding the vendors who sell TMs and other items) or other players who appear in your game when you play online.
4. Return to the Hallowed Tower
After you've interacted with the requisite number of characters, return to the Hallowed Tower on Route 209 and interact with it again to trigger an encounter with Spiritomb. Only one Spiritomb will appear per Odd Keystone, so save your game before you begin the encounter in case you inadvertently knock it out.
In addition to the Odd Keystone you receive from the black belt, you can find a hidden one in Twinleaf Town. You can also find Odd Keystones -- along with other treasures like fossils -- by mining in the Grand Underground.
Pokemon Brilliant Diamond and Shining Pearl launched for Switch on Nov. 19. For more on the games, be sure to check out all the version-exclusive Pokemon and how to get a free Mew and Jirachi.