The Pyrite Bldg (Japanese: パイラのビルPyra Building) is a building in actually made up of two distinct parts. The first section is a rotting, run-down warehouse to the northeast of Pyrite Town. Inside the warehouse, there's also an elevator that will take riders down into The Under. It is a fairly easy place to navigate around, but the large number of guards makes progression difficult.
The top of the warehouse connects to the entrance of Pyrite Cave, an abandoned coal mine where most of Miror B.'s force hides.
Trainers with a Poké Ball by their names may be challenged for a rematch after defeating certain bosses. In a rematch they may have higher-level Pokémon, and any Shadow Pokémon previously caught will be replaced.