The wave has not been addressed. I can tell you what the current prevailing theory is but that'll have to wait until you're basically at the end game, and by then you'll probably have already guessed it. XD

that all reminds me of one time in college I took what the ended up being an EXTREMELY casual class (wish I could remember what it was actually called/about) and ended up writing a comparison on mythological figures used in Final Fantasy vs their actual representation in their respective pantheons. That was fun.

That does sound like fun! And yeah, it's interesting how they just kinda evolved and became their own entities over time. (...though I mean I guess with Bahamut we can think D&D for starting off with making him a dragon instead of a giant space fish to start with. XD)