Quote Originally Posted by waifugenerator View Post
I don't think they even knew where they were going with Zodiark/Hydaelyn back then
I'd even go as far as saying the way these details developed over the course of the game's life may have gone like this:

1.0: Hydaelyn is just the name of the planet, and the Echo is a supernatural power that grants immunity to tempering on top of a platter of other assorted things.
2.0: Hydaelyn is the one true goddess, Zodiark is the Evil God of Darkness and Chaos, and the Echo is the Blessing of Light. You are only immune to tempering because Hydaelyn is personally protecting you.
2.5: Hydaelyn is the one true goddess, Zodiark is the Evil God of Darkness and Chaos, and the Echo and the Blessing of Light are separate things. Thus you can still safely fight primals, even though Midgardsormr broke your Blessing.
4.0: Hydaelyn is the one true goddess, Zodiark is the Evil God of Darkness and Chaos, and the Echo gives you a fighting chance over a primal's influence, allowing you to control them if your will is strong enough.
5.0: Hydaelyn is a primal of Light and ???, Zodiark is a primal of Darkness and Salvation, and the Echo provides no defense against a primal's will if their power is great enough.
5.3+?: Zenos wants to play Planetary Rock'em Sock'em Robots, and he's called dibs on the purple one. (I seriously hope they don't do this.)