Thinking about Ghost Physics feat. Xenoblade 3 etherlore

(Now on Tumblr)

So I've kind of gestured at thinking about this, but since I'm currently writing a fic with lots of mages-talking-magecraft, I'm currently also thinking about how the physiological differences between Kevesi and Agnians probably go far beyond just "one of them has super strength, the other doesn't".

I've settled into thinking about it in terms of the origins of the various species of people. Kevesi are all descended from inhabitants of Bionis and Mechonis -- they're essentially condensations of the natural ether flow of the titans, which makes them very etherically dense. Doing magic with ether requires an ability to circulate ether and condense it as necessary, and the innate high etheric density of Kevesi bodies makes it safer for them to do so. Their mages tend towards all being extremely strong, even if they're not super numerous -- their ability to channel ether is a lot more bestial and unrefined, more comparable to the abilities of various monsters and fiends, but it does also mean that their power is a lot more raw, and isn't limited by their physiology. They're also a lot more resilient against etheric attacks as a result.

Agnians, in contrast, all have Blade heritage. They're all an extension of a designer species characterised by their ability to circulate ether so efficiently they basically leave none for themselves to keep themselves alive. We don't know exactly what changed to make Alresti Blades capable of maintaining themselves etherically, but we do know that they didn't lose much in the tradeoff, staying powerful and physically resilient. Rather than the raw density of ether the Kevesi have, Agnians are more uniform on an etheric level, relying on regular circulation of ether and having far more natural structures for that ether to flow through. However, that does come with some inherent limitations on their ether management -- a soft cap on how much they can "take on" at once before they're overwhelmed and start getting ripped apart on a molecular level like an engine being overdriven. Condensing ether in your body is a lot more harmful and dangerous if all the ether in it is supposed to be dispersed and fast-moving, which also means they're more vulnerable for etheric disruptions in the form of attacks.

Kevesi are stoneware and Agnians are textiles, essentially.

This also means that the two sides, even though they use fundamentally the same kind of etherlore and magecraft, feel very different to each other. Most Agnians have an innate etheric sense, and to them, Kevesi vary from feeling like a powder keg to an overpressurised gas tank, extremely volatile and very, very strong. Kevesi on average don't have an etheric sense, but for their mages, Agnians have a much less recognisable footprint, feeling weirdly "hollow" in comparison to Kevesi bodies. Neither side quite feels like the other are "real" people.

This, of course, complicates cross-kingdom operations, especially for Agnian healers working with Kevesi. Outside of just not having a core crystal to anchor their healing on, Kevesi bodies all maintain pretty strong biological differentiation, and their etheric density is draining if a healer doesn't think to adjust their approach to realise that they're reparing a crack, not mending a tear. Kevesi mages don't struggle nearly as much, since their offensive magic is already tuned to interact with Agnians physiology, and it's far more common for their healers and mages to be the same people. Kevesi healing magic can feel unpleasantly forceful, but that's still a lesser side-effect than Agnian healing magic having a chance of not "taking" properly.