Here is how I see it happening with the Saintess part of this Revenge Story:
Saintess will attack his Darkness with her Holy Magic Hullabaloo
The MC will play along: "I'm melting,! i'm melting! Noooo! Bleh..."
Saintess will gloat about her holiness reveal something she shouldn't
MC will make...
Wait a minute... Doesn't that mean that they have a special method for refining the fruit into medicine?
One that expunges the "hallucinogenic" leaving only the anesthetic effect
So... how they dispose of this byproduct of the refining process could be a major hint
If only MC hadn't been...