Sakashita Iina

She's a girl that Shuuta canvasses into the Scientific Investigation Club.
According to Shuuta, her unique characteristic is her marked lack of any unique characteristics.
Her nature is simple and reserved. She often gets messed around by Shuuta, who's unable to read the mood.
She's affliated with the Concert Band Club.
She likes going around eating ramen.

Spoiler

Her real name is Kaigari Hotaru, codename Messiah.