You know that popular guy in school everyone loves because he's good at everything, says the right things, and bullies the easy targets? Well, in this book, that's the "Good Friar," the kryptonite to Kempe's crying superpowers. Even though he is warned about Kempe's peculiarities and begged to be kind, this dude cannot take her tears. He just cannot.
We all know that Kempe's crying jags get on just about everybody's nerves, so what's another enemy? Well, in this case, we're dealing with a guy who's got influence. He denounces Kempe formally in his sermons (which are fabulous, by the way) and gives the people who already hate her a rallying cry. Pretty soon, even Kempe's friends desert her—including, temporarily, Master Robert—and it is suggested that she get out of town.
No manner of persuasion can divert this guy from his course of destruction. Even when Kempe's clerical friends visit him and ask nicely, the Good Friar is not having any of it. His mission is to destroy Kempe, and he never desists.
He also doesn't win.
While he never relents, Kempe simply drops him from the narrative because she becomes too busy and important. Still, we're left with the sad image of a crying mystic who just wants to listen to the good words of the rock star preacher and be liked by the other kids.