Some of the things you need to do to get specific Pokémon in Brilliant Diamond and Shining Pearl are just plain weird, and Spiritomb is no exception. Rather than a very strange evolutionary path like some Pokémon, you'll have to engage with online features instead.
The process to get Spiritomb is long and will take some time, so carefully follow the steps below to add this Pokémon to your collection:
- Go to Route 208 and talk to the Black Belt NPC. They will give you the Odd Keystone.
- Head to Route 209 and go to the Hallowed Tower.
- Interact with the Hallowed Tower to use the Odd Keystone.
- Make your way to the Grand Underground and interact with 32 different players.
- Return to the Hallowed Tower and interact with it again, and you will have a chance to capture the illusory Spiritomb.
This is the only way to find a Spiritomb in the game and it is one of the weirdest sequences of events you will need to do to mine a Pokémon in Brilliant Diamond and Brilliant Pearl. Don't forget that you will want to have some Fairy-types on your Pokémon team to assist in the fight against Spiritomb.