Darkness
A supernatural being must behave as prescribed by its stage, until the power becomes part of itself. Until the potion is digested, the bearer is vulnerable: the power is already there, but there is no control over it yet.
The night roles: The Sleepless one stays awake while all others sleep, the Midnight Poet turns night into words, and the following stages already work with fear itself.
The method remained the knowledge of the few for a long time: the church hierarchies were in no hurry to reveal it, and many supernatural beings ascended blindly, paying for it with their sanity.