Did we reverse Emet's tempering at the end?

[Cleretic]

I think injecting him with a huge amount of light aether, thus countering his imbalance towards darkness, is exactly the same mechanic our cure for tempering uses.

The concentration and carefulness that we display with the normal cure process later on is cus we're doing it on purpose now, and we actually want the people we're curing to live afterwards. But neither of those things has to be true for the actual aetheric rebalancing that breaks tempering to occur. That's just something akin to a chemical reaction. If you have the necessary components of it present, it'll happen.

Uhm... no, not with tempering. Theoretically a pull like that might've un-Voidsented the mind of something like Diabolos, since with sin eaters and voidsent it's just a gross imbalance between light and dark.

With tempering it's both a gross imbalance and a dilution of the self, and that's not something you could just brute-force with, say, cramming an apocalypse's worth of light in someone's chest. Fixing the sense of self without the aetheric imbalance is going to cause an even more dangerous fanatic, fixing the aetheric imbalance without the sense of self is going to leave someone unsure of their own identity (and is probably SUPER susceptible to additional tempering).

We've not seen a great amount from Emet post-axe-through-the-chest, but I would not describe his lines afterwards, in-game or in that one Tales from the Shadows, as especially fanatical or lacking in self-identity. So not only do I think we didn't cure him of tempering (because that requires a two-dimensional approach, that we were... definitely not doing at the time), we didn't even fail to cure him. We just killed the guy.

Granted, it's a little muddied by the fact Zodiark is a primal of dark aether, and that dilution was through umbral/light aether. But since we do still know that somehow there is a difference between pure dark tempering and voidsent (if not what exactly that difference is), we can still assume it's a two-dimensional thing.