Just beat it an hour ago. Why did they do nothing with Levias (or whatever his name is) being the Wind Fish? Maybe he has to go into Link's mind/soul for him to use the Triforce and that's why one of his reincarnations dreams of him later on?
Also, Groose x Impa creates Gerudo having red hair. But nope! Didn't do it :/
I wonder if Demise being in the Master Sword is why it always needs to be strengthened. He can't escape, but his power weakens it over time.
That would be a good theory/explanation, but when you find yourself asking those kind of questions, just read this Aonuma quote (which I love):
Eiji Aonuma said:While reading over The Full History of Hyrule, its possible that
some parts may look contradictory. For instance, the Mogma race or the
beetle item that appear on the very first story do not appear on any
other game that takes place in the future. Id like to ask everyone
just to enjoy the book and to be broad-minded, and to think that those
parts are the way they are because of the way Zelda games are
developed.
See?
Besides, I doubt the idea of Demise was around for TWW and TP.

