A few more requests came in while I wasn't notified, so here they are.
Murayama, Katase, & Akia- I kinda wish they were requested earlier so I could get them out of the way first, but I can work with this. They'll show up after Irina.
Bennia- A character I've rarely seen brought up, but I'll see what I can do. Who knows when she'll show up.
Kuisha & Coriana- Two people I've seen in other harem stories as additions but never anything done with them. I'll add them along with Seekvaria
A/N: No lie I looked up what they looked like and I thought they were the same person.
Battina- I was slightly confused about who this was. It's supposed to be Rias familiar, but the weird thing is that apparently she has no official name. Not sure when she'll appear though.
Momo Momozono- Yet another case of who the hell is she. She's apparently an voice actress in something Issei and his friends watch. She'll appear after Irina, but I'll have to think about how to make it work.
Tiamat- Another character I see advertised a lot but nothing gets done with them. She'll appear after Rossweisse.
Trihexia- I was kinda surprised to see her of all people requested. She'll appear after Rossweisse.
Y/N POV
I was currently sitting in class when a girl with long black hair and glasses walked in.
???: Excuse me, but the student council president would like to see Y/N.
I got up from my seat and went in front of her.
Y/N: I'm Y/N.
???: Good. Follow me.
We walked through the school for a while. I thought about starting a conversation, but I didn't know if I was in trouble or not, so I decided against it.
???: We're here.
She opened the door and inside was a girl with short black hair and glasses.
???: I've brought Y/N as you requested ma'am.
???: Thank you Tsubaki, come in and take a seat Y\N.
We entered the room and I sat down on a chair.
???: Your probably wondering why you're here.
Y/N: Yes ms...
???: Oh right I never told you my name. I'm Sona Shitori, and don't worry you're not in trouble.
Y/N: Then why am I here.
Sona: I heard you were acquainted with Rias Gremory. I happen to be a friend of hers, so I wanted to meet you. Would you be interested in a game of chess?
Y/N: I guess I could play, but is there a reason?
Sona: Its a hobby of mine. Besides its a chance for me to challenge someone new.
Y/N: I'm not that great at it though
Sona: Don't worry this is just for fun.
Y/N: Then I guess I can play.
Sona: Excellent
She goes over to a table with a chess game set up.
3rd POV
A/n: So I barely know much about chess, so try to imagine a game going on as they talk.
Sona: So how has your time at Kuoh been?
Y/N: Its been interesting to say the least. Though there is something I've been wondering about.
Sona: And that is?
Y/N: Why did the school become co-ed? Don't get me wrong, its interesting that this happened, but it seems like most of the male students have ulterior motives for joining this school.
Sona: I assume you mean the perverted trio.
Y/N: Them and a good number of other male students as well, and why barely any action is taken to stop them.
Sona: You do have a point, and in all honesty it's a real mystery to me and a lot of others why the perverted trio haven't been expelled.
Y/N: (chuckles) I guess it will be a mystery that will remain unsolved.
After their firat conversation, Sona decided to ask about something she was curious about.
Sona: So I've heard you know the supernatural.
Y/N: Not a lot, but a few things.
Sona: Do you know anything about the Sitri family?
Y/N: The devil house with a strong affinity with water magic?
Sona: Yes, what do you know about them?
Y/N: Well the most anyone talks about are their two daughters. The older one being one of the devil kings, and their youngest being considered a genius.
Sona: Is that so?
Y/N: Although if what I heard was true, the younger Sitri is in a strange predicament.
Sona and Tsubaki started glared at Y/N when he said that
Sona: Is that so, how?
Y/N: Well its said that she will marry any man who can match her in wits.
Sona: And what's wrong with that?
She said somewhat annoyed.
Y/N: The problem is what's to stop someone from using magic to get an advantage or win easily.
Both the girls eyes widened after that revelation.
Sona's thoughts: How did I not consider that?!
Coming back to her senses, Sona made one last move.
Sona: And checkmate.
Y/N: Yeah I had a feeling I was going to lose.
Sona: Don't be too hard on yourself, it was an amazing game. If you'd like I could give you some tips.
Y/N: Really?
Sona: Sure. Consider it a thank you for such a good game.
Y/N: Then sure.
Sona: Great. You can return to class now.
Y/N: Alright bye.
Sona POV
Once Y/N left Tsubaki looked at me.
Tsubaki: President, why did you offer to teach him about chess?
Sona: Take a close look at the chessboard.
I say pointing towards the board. After looking for a bit, she realized it.
Tsubaki: You almost lost!
Sona: Precisely. Had I let my guard down a bit longer, he could have won. I never had any game that close against a man.
Tsubaki: But what if you lose?
Sona: That's why I'm going to teach him, I'm going to use it as an opportunity to learn what kind of person he is. Even if he's a normal human, he shows some potential.
Bonus
Y/N POV
After a few chess lessons with Sona, she asked if I could help the student council at times. I accepted and met the other members. They seemed to like me except Saji, the only male. She told me that her and the rest of the student council are devils, on top of that her real name is Sona Sitri. I was actually a bit scared when she told me this because of what I said, but she told me she wasn't mad, in fact she thanked me for bringing up something she never even considered. Right now I was carrying a few papers to a classroom, I entered and placed the papers on the teacher's desk. As I was leaving, I suddenly lost my balance and fell.
???: Hahahahaha!
I looked around for the source of the laughter, but no one was in here. Suddenly a girl appeared above me.
Y/N: Who are you?
???: I'm Bennia. It seems you've caught the attention of multiple people, so I came to see.
All of a sudden she got right in front of my face.
Bennia: You look ordinary, but who knows. I'll be keeping my eye on you. Bye bye.
She then left as I got up mostly confused about what just happened and left the classroom.
I know someone requested Sona's peerage as well, but like Riser's I couldn't think of anything. If there is anyone you would like to see leave a comment.