Mob-Chan

She is one of a many members from Justice Realization Committee and acts as Trinity's disciplinary committee. Their job is basically to enforce discipline within the school as well as deal with any troublemakers looking to disturb the peace. All of the JTF members have a red halo, black wings, a choker around the neck, and a black and red sailor uniform in common. In particular, the black uniform is exclusive to this committee, and it seems that the school doesn't have many spares in stock.