The Otherworldly must behave as their level dictates, until the power becomes part of them. While the potion is not yet digested, the bearer is vulnerable: the power is already there, but there is no control over it yet.
The roles of the Path are tied to influence: the Advocate speaks for others and knows the value of a word, the Briber finds that value in everyone, the Count of the Fallen rules those who have already agreed.
The method long remained the knowledge of the few: church hierarchies were in no hurry to reveal it, and many Otherworldly rose blindly, paying for it with their sanity.