Here's how:
1. Talk to the Lake Guardians' guardians: After freeing the three Spirit Pokémon, you will be able to talk to the guardians of the Lake Guardians. You will find these guardians near the locations where you rescued the Spirit Pokémon:
* Cresselia's Guardian: Near Lake Acuity.
* Heatran's Guardian: Near Lake Verity.
* Regigigas' Guardian: Near Lake Valor.
2. Obtain the keys: Each guardian will give you a key after you speak to them. These keys are necessary to access the Lake Guardians.
3. Access the Lake Guardians: You can access the Lake Guardians by going to the locations where you found them originally:
* Cresselia: Lake Acuity
* Heatran: Mt. Coronet
* Regigigas: Lake Valor
Note: You can capture the Lake Guardians once you have defeated them. This can be done by using Poké Balls.
Here's a summary of what happens after freeing the Spirit Pokémon:
* Unlocking the Lake Guardians: You gain access to three powerful Pokémon, Cresselia, Heatran, and Regigigas.
* Completing a major storyline: You finish a significant part of the game's storyline related to the Spirit Pokémon and Lake Guardians.
* Expanding your Pokédex: You can catch these powerful Legendary Pokémon, adding them to your Pokédex and increasing its completion.
Freeing the Spirit Pokémon opens up a whole new set of challenges and rewards in your Pokémon Diamond journey!