The Otherworldly must behave as prescribed by their stage, until the power becomes part of them. Until the potion is digested, the bearer is vulnerable: the power is already there, but there is no authority over it yet.
The roles of the path are built on temptation and crossing the line: the Criminal breaks the law, the Apostle of Desires promises the fulfillment of desires, the Devil and the Demon trade these promises in earnest.
The method long remained the knowledge of the few: the hierarchs of the churches were in no hurry to reveal it, and many Otherworldly ascended blindly, paying for it with their sanity.