Natsumi Koizumi

She is one of Otome’s lackeys. She is a student in class four who is the most informative and interpersonal friend of Otome and bullies Kotonoha. She and Kumi Mori take charge when Otome's not around but she and Kumi Mori are slightly less cruel than Otome and in the event Makoto does come to Kotonoha leaves her alone.

(Source: School Days Wiki)