The Otherworldly must behave as his level prescribes until the power becomes part of himself. 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 scholars: the Priest of Secrets keeps and passes on the hidden, the Mysticologist breaks down rituals into parts, the Sage answers those who came for an answer.
The method remained the knowledge of the few for a long time: the church hierarchs were in no hurry to reveal it, and many otherworldly beings ascended blindly, paying for it with their sanity.