Kaitanrm

I am rereading the Wax and Wayne series and find myself wondering what happens to a traditional metal mind that has already been Invested. What happens if another Feruchemist adds more Investitire? Does the metal bifurcate the stores to allow both Feruchemists access to their individual stores? Is it impossible to add to the exiting metalmind without first unsealing it? In the same vein, what happens to a metalmind, like the Bands of Mourning, if the Nicrosil is removed? Is it possible to do so? Or does the Investiture in the companion metalmind split or become inaccessible to all who try to use it?