Here's why:
* The Griseous Orb is a specific item in the main Pokemon games. It's used to evolve Giratina into its Origin Forme.
* Pokemon Battle Revolution is a spin-off game. It focuses on online battles and doesn't feature the full Pokemon world, including items like the Griseous Orb.
To get the Griseous Orb, you'll need to play a main series Pokemon game. It's usually found in specific locations within the game's world.
Let me know if you have any other questions about Pokemon Battle Revolution or the main series games!