So this is a old story:
https://www.mmorpg.com/final-fantasy...ers-1000013673
But Yoshida P would love to do a crossover with WoW or Diablo.
Considering the Void and the Light have similar attributes in FFXIV, the lore in essence is compatible.
So this is a pure theory crafting topic, if such a crossover happened (as it most likely won't) what would be possible lore implications?