The 18-year-old student council president at Honnouji Academy, and the main antagonist. Because her mother leads the school's board of directors, Satsuki dominates the school to the impotence of its principal and teachers. She administers Goku Uniforms to students based on their skill sets. She wields a katana named Bakuzan (縛斬) and possesses the Kamui Junketsu (純潔, lit. "purity").