this new interpretation implies... well for one thing, that umbral and astral aren't elements or even polarities in and of themselves but behaviors that mortals ascribe to the elements. which i guess is fine. BUT ALSO! that bahamut's calamity was indeed an astral(Norv umbral) calamity... based on the fact that the abnormal phenomena in the Source around 4.4/4.5 were the result of an upsurge of umbral(Norv astral) energies.

Prior to the end of release FF14 we saw dramatic political upheaval as old military orders once again mobilized; ancient combat arts rediscovered and passed on to a new generation; a revolution in the accepted orthodoxy of crafting held by all the guilds on Eorzea; the arrival of mysterious strangers from across the sea following a terrible prophecy; the rise of doomsday cults and a mad, traitorous Legatus; the moon falling out of the sky... even mice got like... VERY big. In short, absolutely everything changed in every possible way all at once; the very opposite of stillness and stagnation. With the alternate explanation for what light and darkness "represent" presented by Urianger... the 7th umbral calamity being "light-based" checks out, i figure.