Celestial Realm

The Celestial Realm is a location in Bravely Default. It is said to be the realm of the gods where no war or strife is experienced.

Story
Ouroboros wishes to invade the Celestial Realm using the power of all the worlds Airy has linked, and conquer it and create war and chaos there. During the battle, Ouroboros becomes strong enough to open a portal to the Celestial Realm, but he is destroyed by the Warriors of Light before he can breach it.

It is strongly implied the "Celestial Realm" is the real world, and the "gods" Ouroboros refers to are the human players playing Bravely Default. When the portal opens, the camera on the Nintendo 3DS activates and projects its image into the background in the portal Ouroboros draws attention to, likely causing the player's face to appear in the portal looking down on the battle.