I'm really curious about Meroron's reasoning now. At this point, she's pretty openly antagonistic towards the Precures. This can't be petty jealousy - she was annoying before, but not outright evil. But I can't come up with an excuse for her acting like she does instead of sitting down and talking with her allies, disliked as they may be. I also think that Meroron is a dark fairy, she was most likely born from Darkine herself, with the Chokkiri-dan being her "siblings".
The only thing that comes to my mind is "I hate you because you forced Purirun into losing her memory of you", but this doesn't make a lot of sense, even for her. Maybe, if she's indeed born from darkness, then her dark side is starting to show, and she will get worse before someone has to punch some sense into her.