As of yet, the blue-haired girl apparently doesn't have a name, and is just labeled Mobuko or "Minor character(+ ko*)" along with the other classmate of Senka's.
You look like a pervert.Wh, which one is your sister?ArimaStop it.Stop it.Just ignore herNo matter how you look at it, it looks like you're the little s–How sad...Visual molestation modeSorry, I'm going home with my little sister today.LITTLE SISTER!?I wanna see!!Damn...Stop it.Onee-chan!It couldn't be that huge-boob lady!?I can almost see her panties!!
Waddya mean, 'couldn't be'Sorry to keep you waitingFuck off...But...Arima~ Wanna go somewhere on the way home?I'll kill you, bitch.Arima's little sisterA friend of yours?