Having read about Aetherius, it occurs to me that not much is really known about it at all. Of the realms that exist within it, I only know of two off hand: Sovngarde and the Mantellan Crux. Has there ever been any hint of other planes that exist in the Heavens? I would think such a higher dimension would contain a great deal of secrets but someone, some mage or scholar, must know of more than these two.