The Great Game
The Eternal Empire is a compact between the different Eternal Masters, keeping the peace, and preventing the great dragons from tearing the sphere apart in a self-destructive conflict. However, expansion of their power is in the blood of the dragons, and so an outlet must be found.
The Great Game is it. The primary rule of the Great Game is that the Eternal Masters cannot fight directly against each other. There are many other rules, many of them unknown to any but the Masters, but that rules is the most important one.
The Eternal Masters can still fight indirectly, through pawns and vassals. The more indirectly, and the less force that is applied, the more points a participant scores from its peers. The plans of the Great Game can span centuries, seeking to topple worlds from one dragon into the claws of another. Worlds, resources and prestige are among the prices of this game played by the Eternal Masters.