Here's why:
* MetalGarurumon's evolution line is exclusive to Digimon World 2. In this game, you can evolve a MetalGreymon into a MetalGarurumon with the right training.
* Digimon World 3 features different evolution paths. You'll need to focus on training your Digimon to evolve into the specific line that you want.
However, you can get a similar Digimon:
* Wargreymon: This is a powerful Digimon that evolves from an Agumon and is closely related to MetalGarurumon in terms of strength and appearance. You can obtain it through a specific evolution path in Digimon World 3.
Here's how to get Wargreymon in Digimon World 3:
1. Start with an Agumon: Agumon is the starting Digimon for the game.
2. Train your Agumon: Focus on training it in its growth stages (Rookie, Champion, Ultimate, etc.).
3. Evolve to WarGreymon: Through proper training and evolution, you'll eventually be able to evolve your Agumon into Wargreymon.
Remember: The specific training methods and evolution requirements for Wargreymon are detailed within the game.