I love how Leafy was written in BFDIA 25 (Spoilers ofc)

I love how Book and Leafy were paired so we can finish her arc. Because they're almost the same character, but in reverse.

Both of them are people pleasers and they desperately want everyone to like them, however..

Leafy begins being generally kind to everyone, but overtime, she gets really violent towards people if they reject her, or don't return a favor. Even when she gains real friends near the end of her game, her emotions get the better of her, and ultimately cause her downfall.

Book, however, begins her game being kind of violent. Think about her fight with fries, the freeze juice, etc. However, overtime as her allies start to fall, and she gets put in hard situations, she becomes softer.

Book tries to have an honest and open conversation with leafy, because overtime, she's learnt that honesty can solve conflict. However, BFDI is naturally a very zany show, where characters are all over-the-top and can't always communicate well. Book tries to get through to leafy, but leafy doesn't listen. She stays how she is. 

And we get to the end. Book pretends to kill leafy, in line with the image she had at the beginning of the game. However, it's revealed that she actually left a note to leafy, telling her she has to leave for her own good, and surprisingly, she listens.

And Book's advice seems to retroactively have an effect on her. BFDIA's main theme seems to be "growing up", and Book choosing to spare leafy, even when she has been arguing with her is a sign of true maturity. 

It should also be noted that Leafy is written in a way that other find to be indicative of a mental illness/personality disorder. While I do not have these disabilities and neither am I an expert, it makes sense. People with these mental disabilities can feel as if they're always in the right, or that everyone's out to get them. I think it's an overall positive message when you look at it from this lense that Book would help leafy. 

And to clarify, I am not insinuating that Leafy is immature, she has gone through trauma and may actually have a disorder. What I am highlighting by talking about maturity is book's growth. I am not ableist.