Big post edit needed.
I think coming at it from the D&D alignment chart is mistaken from the outset because this isn't a matter of personal or societal outlook but of cosmogony. Light and Dark aren't good and evil, they also aren't law or chaos, they are Order and Chaos or Genesis and Entropy under an entirely separate definition.
The core breakdown comes because Darkness and Chaos have been bundled together, but Zodiark's endgoal is what in that D&D dichotomy would be a pure Lawful existence. All things are returned to it in a stagnant sterile existence. It is not a world of pure D&D style chaos where the capability to see your desires becomes truth, but one where Zodiark is singularity of creation.
"So indomitable is his strength that all things are by him twisted and pressed into oblivion. He alone fashions the laws governing all things, and administers punishment in place of the gods. So is he Keeper of Precepts, and his authority is absolute."
The name Zodiark was chosen for a reason, and Zodiark as 'Keeper of Precepts' is the very essence of lawfulness, but not necessarily Order.
Zodiark's Chaos is the whirling blender of pure energy that is the Aetherial Sea from which all things came and to which all things return. And for whatever reason, He wants all of it and for nothing to develop into any manner of being outside of that state.
Hydaelyn's demonstrable power, as when we separate Lahabrea and Igeyohrm and he responds "How dare you bring Her barriers back upon me!" is to create distinctions, not an enforcement of societal laws but the creation of natural ones like how fire and water are different things, how we are different people. To make a comparison back to SMT, a god of lawfulness would not so cherish free will as to give up Minfillia as Word of the Mother because an automaton would more directly communicate Her will.
According to the Gerun Oracle - which Word of the Mother paraphrases in her explanation of the cosmos to WoL and Elidibus gives to Urianger as the truth of creation - mortal life is Her creation and the very bulwark which prevents the return of Zodiark, and Zodiark hates us. She created, and by that creation we with our free will achieve D&D's chaotic nature because of individuality, but that's incidental.
Some have stated we've been an instrument of lawfulness thus far but that is absolutely incorrect. Garlemald was built to spread strife but it does so as an entity of rigid lawfulness, Ishgard as a society was dogmatically lawful in its extreme until we came along. All of our major enemies have been agents for lawful organizations with the exception of Zenos who does what he does to try to feel anything.
Light and Dark are not Astral and Umbral, either, according to Koji Fox.
Quote:
So, you have the elements—and it’s still six elements, there are no newly-discovered ones. Those elements have charges—umbral and astral. If something has “umbral energy”, it is one or more of those elements, individual or combined. So if elements have an umbral charge, it can be said that they are “umbral energies”. That’s where those terms come from, “astral energies” and “umbral energies” are not individual things, it’s a blanket term. Light and Dark are not elements, but they are energies…in a different sense. They are not elements, they are not of the elements, and they are not astral or umbral. It’s a different type of energy. You might see a Light and Dark sprite and think, oh, they must be elemetals, but those are made of an entirely different form of energy.
