Something that really interests me is the feruchemical storage of investiture in nicrosil, because there are so many ways it could work. Would it be storing specific kinds of investiture, like allomancy, stormlight, or breath, or does it store generic investiture, like you store stormlight investiture, but draw on it on Nalthis, would it come out as stormlight or breath? Could you compound it to create breaths or stormlight? Does it store specific abilities, like could a mistborn just store one ability, or all of them? Would a windrunner store their specific abilities? And then what about Renarin's lightweaving? He somewhat foretells the future, so would drawing on that show the same thing or would it show something different? What about hemalurgic investiture, could that be stored?
I think about this stuff too much.
