The Otherworldly must behave as his stage prescribes, until the power becomes part of him. Until the potion is digested, the bearer is vulnerable: the power is already there, but there is no mastery 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 long remained the knowledge of the few: church hierarchies were in no hurry to reveal it, and many Otherworldly ascended blindly, paying for it with their sanity.