[Lokean]

Again, I question the problem with spatially distributing them. Say the glorious Ermorian legions, sent into the Utter West on a mission for the New Faith, seeking the means to bring about the immediate reawakening of the New God. There they open the tomb of an old god, thought by the Pontifices to be long reduced to a divine spark, devoid of will, and his malevolent spirit consumes them utterly, tearing the veil between Life and Death. Now, with the very land beneath their feet corrupting as they march, the vast and growing legions of undeath march on the tomb of the New God, far to the east.

Now, obviously, that could be done better, and would vary considerably based on how the players wish to approach it, but I don't see that it's *that* farfetched, Nor does it really change the theme for either nation. In fact, about the only change is the capital of Ashen Empire being some mouldering tomb complex rather than a mouldering shell of Eldregate.

EDIT: I don't have a problem restricting nations to only one incarnation each, since it's really just to increase the chance of somebody getting their favorite version of a nation, but I'm just trying to illustrate that I don't see a loss of thematic quality going hand-in-hand with multiple eras of the same nation being in the game.

Agartha, I'll admit, is a little harder, but if you multiply them into a once world-spanning civilization that has collapsed into a few pocket-cultures in deep cave complexes I think you can still make it work quite readily. One culture never encountered humans, one was slowly replaced by them and the last was worshipped and fell into decadence, eventually becoming a nation of hallowed mummies.