The Otherworldly must behave as prescribed by their rank, 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 heavy in themselves: the bearer passes through states from which an ordinary person does not return, and must remain themselves in each.
For a long time, the method remained known only to a few: the church hierarchs were in no hurry to reveal it, and many Otherworldly rose blindly, paying for it with their sanity.