Satsuki Kiryūin

the president of the Honnoji Academy's Student Council and the initial main antagonist in the anime Kill La Kill, but later becoming a deuteragonist after her plans to overthrow her mother's Life Fiber fashion industry came to fruition. She is later revealed to be the older sister of Ryūko Matoi who she thought had died after a failed experiment to fuse her body with Life Fibers and the two join forces in order to defeat their mother, Ragyo, in the climactic battle against the Life Fibers, who sought to enslave and destroy the human race