Mizuho Kanou

Sixth grade, St. Miator.
One of Shizuma's entourages who help her do her work as the Etoile. She has long, dark hair styled in a hime cut.

In the first episode she is the one Nagisa mistook for the Etoile at first. The reasons to this could be either because she was the last in the crowd to stand up, or because of her refined looks.

Later on, in charge of props in the drama club at Ichigo-sha.

(Source: Wikipedia, translated)