To complete your national Pokédex for Pokémon Brilliant Diamond and Shining Pearl, you’ll need to find Eevee. But it’s not as easy to find as most Pokémon in the game.
There are some big requirements you’ll need to find Eevee. First, you must beat the Pokémon League, and you must have completed your Sinnoh Pokédex and unlock the National Pokédex.
Then, starting in Hearthome City, head south to Route 212 and stay all the way to the right. Eventually, you’ll come across a garden, a brick fence, and a huge house.
Talk to Mr. Backlot every day until he tells you there are Eevees in the garden. Each day, there will be a different Pokémon in his garden. On the day Mr. Backlot mentions Eevee, the Butler will say that the Pokémon doesn’t exist in the garden, but if you go to the back of the house and rifle through the grass, there’s a chance you’ll come across an Eevee.
If you’re looking to get the Shiny Charm, make sure you capture Eevee and use it to get all of the Eeveelutions to complete your National Pokédex.