The Hunger

The Hunger  is a sentient plane that feeds on other planes. It serves as the endgame, main antagonist of the Balance Arc campaign.

The Stolen Century
The Hunger is first encountered by the Red Robes as they are leaving their home planet. It then starts attacking and feeding on their plane, forcing them to escape. It later manages to find them again in another plane, and it starts attacking and devouring that plane as well. The Red Robes then watch as it grows slightly bigger from devouring the plane they were on.