Zodiac lore question

[Anonymoose]

Honestly, I don't remember the specifics in great detail, but I'll look around.

As far as I can tell, they're using aetheric science to magnify the effects of the natural phenomenon of spiritbond. First, they forge an Arm of Eld, and then you aetherically treat it six ways from windsday using mist-elixirs and atma-crystals and augmented fields of interacting materia from other gear you've worn and the aether of your fallen foes... and then you take that overcharged weapon that's been with you for that long and convert it into a materia, which you then "awaken" by using it in combat drinking more aether and atma-crystals.

I would hazard a guess that the aetheric field coming off of the thing is by now specifically attuned to you (as you might attune to an aetheryte), whereby the weapons have become a part of you and in your hands its easier to wield and responsive to your experience, personality, and needs. That attunement might be so strong that the aether is essentially sharing in / mimicing your lifeforce / soul / whatever. Anyone else would likely experience some kind of disharmonic clash that would make it impossible to properly wield.