Satsukitane Mikako♀

Mikako is is the student body president and an upperclassman of Tomoki and Mitsuki. Mikako is a childhood friend of Sugata, whom she calls "Ei-kun", and is the daughter of an influential yakuza boss in Sorami. She is manipulative, cunning, highly intelligent, athletic and sadistic. She initiates many schemes in the form of festival competitions that place Tomoki in humiliating situations for her amusement. Unlike Sohara and the Angeloids, she directs her romantic affections towards Sugata.

[Edited from Wikipedia.]