Let’s assume a Feruchemist has access to some other form of Investiture, maybe with a Perpendicularity, liquid Dor, becoming a Radiant, getting Breaths, or maybe even tapping Connection to become Elantrian or something. We’ve seen from TLM that Allomancers can use Investiture from a Perpendicularity instead of metals, so can Feruchemists do the same? If so, how would something like a coppermind work, where the attribute has data stored rather than just an amount? There’s probably a WoB explaining this somewhere, but I can’t find it.
Oh correction 2012, this is the oldest WoB I can find on the subject, and says basically the most he has ever said about it
FireArcadia Is there any use to being a copper Compounder, from a Feruchemical point of view? I think the same point would also apply to an aluminum Compounder.
Brandon Sanderson Some combinations, like some abilities themselves, aren’t really that useful. That said, being able to Compound copper…that could do some things. Aluminum, not so much.
https://wob.coppermind.net/events/105/#e1131