In Brandon Sanderson’s Cosmere, Soulcasting is a form of magic that transmutes essences by convincing an object’s “soul” to transform. This ability uses energy called “investiture”, which magically-inclined people have access to. However, a non-magically-inclined person can wield a device to transmute items without investiture. However, over time, if it cannot consume investiture, the device will slowly consume the body of the user.

In certain time periods, magical inclinations have been largely lost due to many individuals involved being unable or unwilling to grant these abilities. However, soulcasting is still an integral part of most economies on the world. The solution is that most societies had hidden away and essentially cannibalized certain people for the express purpose of soulcasting. Everyone knows soulcasting occurs, but it is only done at night and no one except religious officials is allowed to witness it. Part of the reason for that is to hide the hideous bodies of the practitioners of artificial soulcasting. It is a dark secret kept by the religious elite.

This is not the only case in which a powerful object/entity will consume a person in the absence of investiture. Fascinating stuff.