It would be better if Arisa is "imaginary" twin. Nina pretending as she is "Arisa" role playing another character. And let Shizuku discover it at the end.
Still is possible that NTR would be a tag related to imaginary character of Nina.....
Anyway, it's not bad like this. And for sure Shizuku isn't the first friend which Nina invited.
I hoped that Arisa was actually Nina. What a twist )
Yeah, same. I already wrote my previous comment, and just found yours.
Also, after all I'm getting, Arisa eventually stole school uniform from Nina, or it's strange how Nina has a twin and Shizuku does not know it... Only if twins go to different schools.
And Arisa role-played Nina.