Kyouko Equuleus

小馬座（エクレウス）の響子

Kyouko is Shouko's elder sister and the previous Equuleus Saintia. [Spoiler] Kyouko sacrifices herself in order to avoid Eris of possessing Shouko. Because of this act, Eris possesses Kyouko's body instead [/Spoiler] (Source: Seiyapedia)