User blog comment:EmpyreanSmoke/Supernatural Q&A (Closed)/@comment-27014555-20151105120417/@comment-3045936-20151110044607

If a soul is magical in nature. As it is, in the series. Hence why it can be used for supernatural power sources and spell. But like all Magic. Any created from it, can undo it. Maybe only God can't destroy a soul. As he created them, knows what makes them tick.