They hold a mysterious orb of power. It's stored in a special cradle here, and protected by their best guards. While they hold the orb, it provides an advantage to their side not just in the borderlands, but in the eternal battlegrounds as well. We can capture the orb by holding one of these three keeps and depositing their orb on an altar of power. Doing this will deny them their advantage and provide one to our side instead. Controlling the orb could well prove our key to victory.