Pokémon Hideaways

A new feature to this game is the Pokémon Hideaways. There's different biomes in each of the areas of the underground, and you can find wild Pokémon throughout the areas. Many Pokémon are exclusive to these Pokémon hideaways and more Pokémon appear at various points of your progression, with the National Pokédex being the feature that adds the most. Through this, nearly every Pokémon in the National Pokédex to Sinnoh

There are five different pointss where more Pokémon will start showing up: Get Defog
Get Strength
Get Icicle Badge
Get Waterfall
Get National Pokédex
With each milestone comes more Pokémon, though the most Pokémon come with the National Pokédex

Each Pokémon also has a chance of having one of their Egg Moves when you catch them in the Underground.

Whenever you enter one of the Hideaways, there is a small chance of a "Rare Spawn" appearing. Rare Spawns are Pokémon not in the Sinnoh Pokédex and can appear at any time.

The level of a Pokémon in the Hideaway is dependant solely upon your level. While some Pokémon unlock when you reach certain milestones, these levels are set based on your progression in the game

The Pokémon you can encounter can be altered by using Statues in your Secret Base. When you place statues, there will be boosts to specific types and the type with the highest value (based on size, type of statue etc.) gets boosted. They can get slightly boosted, boosted or severely boosted. These will only boost the spawns in locations where Pokémon of that type exists.

Click here for full details on statue manipulation