『Sakiko Togawa』

A first-year student in Haneoka. Sakiko is refined girl who comes from a rich family, and used to attend Tsukinomori Girls' Academy. She often plays the piano in the school's music room.

She is the keyboardist and leader of Ave Mujica. Her stage name "Oblivionis" based from Lacus Oblivionis, meaning "Lake of Forgetfulness".