Forgery hacking Soulcasting?

[Trusk'our]

Part of Forgery works on the principle of believability; if you try to make a Soulstamp that is far removed from what could have happened, it will either only stay a short time, or it will not work at all. This means that under normal conditions, changing a material from once substance to another would be basically impossible. But if you were to use a Soulstamp on something that was Soulcast, could you change it back to its original form? Could you change it into a different material than what it originally was Soulcast to? Could you use a Forgery on an object that never had been Soulcast, but change its past so that it had been Soulcast? If you were to Forge a rock that had been Soulcast from air back into air, would the Forgery fall apart? If it did, would it return to being a rock in its original form, would it turn into a rock cloud, or would it stay air?

Edited December 30, 2021 by Trusk'our

[Quantus]

Some things like this will inevitably become more viable as the Cosmere moves into the Space era when Crossover between magic systems would be more Likely by simple numbers.  

WOB says stamping metals to a different one is possible but it would unravel when the stamp is damaged and so not work great for allomancy (as the example use in that WOB). 

But Forgery, much like the Commands of Awakening, are all about how you invasion the History of the Object.  You'd have to reach all the way back to star creation to change the atoms of a lump of metal, but it's a lot easier to re-write a ring to have been crafted (or even just purchased) with Silver instead of Copper, for example.

 

Personally, I think the true power of this combo goes in the other direction: Soulcasting makes permanent changed to an object or person from the spiritweb up, but the Radiant and Spren both have to do understand, envision and hold all the details in their minds to pull off anything complex, and the further from the target's current self-Image the harder it is to make the Change.  Forgery is temporary, but it's a Far more complex Language for making alterations to a Spiritweb.  So you Forge a person and then use Soulcasting to make it permanent by telling the object to just "Be This Now" and providing the Investiture to make the change stick.