Wild beyond the Witchlight Help

Fellow DM here. While I am not running this module, I do need help involving this module.

I don't have the book and only know surface level things of the module.

I have a character in my group who has a backstory involving the carnival. They were a part of the carnival for some time and eventually wanted to escape, so they did.

How would witch and light react ? Would they occasionally send people to bring her back?

Also, could someone give me a run down of who those NPCs are? She mentioned Witch and Light. Are they the ring leaders? Are they nice? Mean? Psychotic? Etc. I really don't know much about them and I don't own the book. Any and all help is greatly appreciated.