I know this story has ended, but let me just post one thing on this book. What if (Y/N) and Jeanne Alter has voice lines in Megadimension Neptunia VII? Let's take a look on what I had in mind:

Introduction: Hello there, I'm (Y/N) (L/N). I hope we can get along with each other nicely!

Birthday: Today's your birthday huh? I'm surprised, I've got nothing to give you a present, but the only thing I can do for your birthday is to hang out with me, that'll be your only gift, sorry if I was being rude there.

Christmas: Merry Christmas! Well, we've spending time together for the past few days ago, let's have some fun throughout this month of December!

New Year's Eve: It seems like this year is over now huh? It's been a lot of fun though, I hope we can do this again next year, okay? 

New Year's Day: Eyyy~! Happy new year! Well, since today is New Year's Day, let's go hang out with the others, maybe we can do something fun today!

Valentine: Happy Valentine's day! Here's a chocolate for my dearest friend! Hm? "It's not hand-made" you say? Ehehehe...yeah, it's not hand-made. I'm not really good at making chocolates on my own, other than Jeanne. 

Rejection: Dude, can you not do that to me while I'm doing something? Otherwise, I'm gonna just gonna have to knock you out for bothering me.

Other 1: Heil~! Heil~! What's the matter with your head~? Oh yeah~! Oh, hey there! Ehehe...Sorry about that, I was just singing.

Other 2: 

https://youtu.be/Uu6jLyBrmB8

Jeanne D'Arc Voice lines:

Introduction: I'm Jeanne D'Arc, and (Y/N)'s my idiot. Try not to do anything stupid, got me?

Birthday: Humph, what's the celebration? Your birthday? Shall I have Fanfnir lit up the candles for you?

Christmas: It's Christmas huh? Well, let's just...you know? Hang out and stuff? Just like (Y/N) did to me.

New Year's Eve: This year is now over...*Whispers* Heh, let's do it again next year. Eh? Did I say something? Bah! It's none of your concern!

New Year's Day: Happy New Year or...whatever. Let's just do something that your mind can occupy with me.

Valentines: (The same thing from Jalter's Valentine's Day Event).

Rejection: Hmph, I would wish to hang out, but you're just some bug who's in my way.

Other 1: H-Hey! What are you doing with my N-Nintendo switch?! Give it back! There's nothing for you to look in there!

Other 2: You know...(Y/N) was my idiot when I first met him, now then I met you...you're also an idiot as well. I-It's not I like you or anything, I'm just calling you an idiot, that's it!

(A/N: Alright, these are voice lines on what I can think of. Tell me what you think!)