Raichou Hiratsuka

The Head of the Supernatural Phenomenon Treatment Bureau as well as known by being its greatest traitor, the Bureau's biggest mistake, and by Ouka as "The Empire's Terrorist". She is the young butterfly girl (codenamed: Electric Butterfly) that cameos in almost every episode as a background character up until episode 13. At the moment it is unknown to what she has done but Ouka states that "even the death sentence wasn't enough". She usually acts and talks innocently but is very cryptic and seems as everything she does has an ulterior motive; even frightening Chika with her presence alone. A running gag is most of the time she is about to eat something sweet right before something happens. She is named after the feminist writer Raicho Hiratsuka.
Source: Wikipedia.