Certain Pokémon are hard to find and even harder to evolve depending on the game you are playing. In Pokémon Brilliant Diamond and Shining Pearl, the classic Bug/Flying-type Scyther happens to be both.
Because BDSP is a remake of the original generation four titles, Scyther is exclusively obtainable in Brilliant Diamond, while Pinsir is available only in Shining Pearl. This means anyone who wants to hack and slash with Scyther or eventually get Scizor—one of the most used Pokémon in competitive play in 2006—will have to do some work.
For players running through Sinnoh in Brilliant Diamond, Scyther is obtainable in two ways: in the wild on Route 229 and as a rare spawn in certain Pokémon Hideaways in the Grand Underground. The first option, however, is located right above the Resort Area and is only accessible in the post-game.
Players trying to be Bug Catchers in the Grand Underground can find Scyther in the Grassland Cave, Riverbank Cave, Still-Water Cavern, and Big Bluff Cavern as a rare spawn. You don’t need to meet any prerequisites to encounter the Mantis Pokémon either since it is available as soon as you get the Explorer Kit in Eterna City.
Once you are ready to evolve your Scyther into a Scizor, you will need to track down a Metal Coat on Iron Island or via capturing Pokémon that can hold it in the wild and trade with a friend. Once you receive your Pokémon back, it will be the popular Bug/Steel-type that dominated the meta in Diamond and Pearl.