I'm happy for my soul to be immortalized in the blockchain, after I clear up a few things. Is this like a one time deal whereby my soul is forever the property of Mephistopheles, or is it simply a contract that allows Mephistopheles to bargain for my soul? If I give up my soul, can I purchase/trade other souls on the blockchain? Also, does my soul have to be currently damned to be eligible, or can the damning be done later?