The Otherworldly must behave as their stage prescribes 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 control over it yet.
The roles of the path are creative: the Planter cultivates the land and grows crops, the Doctor heals people, the Druid lives in harmony with nature, not on top of it.
The method remained the knowledge of a few for a long time: the church hierarchies were in no hurry to reveal it, and many Otherworldly ascended blindly, paying for it with their sanity.