What do i with the key you get in aegis cave Pokemon mystery dungeon explorers of sky?

In Pokemon Mystery Dungeon: Explorers of Sky, the key you obtain in Aegis Cave is known as the "Great Hall Key". It unlocks the Great Hall, a secret room located within Aegis Cave.

To access the Great Hall, follow these steps:

1. Enter Aegis Cave.

2. Navigate through the cave until you reach the "Aegis Cave B1F - Junction" area.

3. From the Junction, head northwest and go up the stairs.

4. Continue straight ahead until you reach a door with a keyhole.

5. Use Great Hall Key on the door to unlock and enter the Great Hall.

Inside the Great Hall, you'll find various hidden items and treasures, including rare evolution items, TM's, and items useful for upgrading your guild.