[quote=@Kimiyosis]
Wait, the classes have been sorted?
[/quote]

No, Black class is the upper echelon members of the school they conduct activities without some of the other student's knowledge and act without the other student body knowing. They also get free stuff, and have a soft ball team, so they are really the super elite of the school and do some of Saya's dirty work with out the student's interfering, there are more than just Izumi,Kaede, and Doughnut (Donna) in black class a set of Npcs are there too, mostly they are people that are 3rd year students.