(Futaro and Hiroki) Part 6 and final.

You meet your twin brother Futaro after receiving a beating from Kokujin and being humiliated in front of your girlfriend Nao.
Futaro: Man, not fighting again. You know Mom doesn't like it when you fight . I'm still studying my notes. Hiroki: Dude, don't say anything to her, but if it happens again... but this time it was different. Some good-for-nothing messed with Nao, and I wasn't going to stand idly by . (Shrugs) Futaro: (Gives you a side-eye) I can't blame you. You take after our father. Hiroki: *(Laughs) Seems so... Futaro: Tomorrow I have a tutoring session with a group of quintuplet sisters... so once I'm free, I'll help you solve your problem, and we'll hand it in like old times. We'll ask Ayumu for help. Hiroki: Thanks, bro. I owe you one. I'll get to training. This isn't over.
Futaro: Fine, but do it quietly. I'm trying to study.

(Days after the incident with your twin brother Hiroki, you are hired as a private tutor for the Quinillionaires.
You help them study and so on, but you hear a rumor that this Kokujin guy wants to get involved with your sister Kanako.)

???: Are you Futaro Uesugi?
Futaro: Yes, that's me.
???: My name is irrelevant for the moment, but I have to inform you that the new exchange student is having an affair with your sister-in-law Nao.
Futaro: What?! Who the hell are you? Speak up already!!!
???: I already told you, it's not relevant at the moment, but I hope you're alert. Their next target is Kanako....
Futaro: My older sister...
???: That's right... Anyway, I already gave you the information...
Futaro: I don't know who you are, but thanks...

Futaro:* I exhale the air from my chest and hang up, then grip the phone tightly.

The following characters will appear in this story.
kokujin- Nao - kanako Mori-kaede uesugi
Isanari Uesugi, Raiha Uesugi, Futaro and Hiroki Uesugi, and one or two appearances of the Nakano sisters, but that depends on how you handle the story.
ichika-itsuki-nino-miku-yotsuba.
appearance of extra NPC-type characters.
teachers, shopkeepers, etc., you name it.
In this part you are Futaro like in part one but...with the difference that you are worried about your twin brother and you help him train even though you don't like violence.