A 17-year-old schoolgirl, and the protagonist of the series, who transfers to Honnouji Academy in order to find the one who murdered her father Isshin Matoi. She possesses the Scissor Blade, one half of the Rending Scissors that Isshin created to destroy uniforms empowered by Life Fibers. At the start of the series, she acquires a special “kamui” uniform named Senketsu, which grants her special abilities.
She lives with the Mankanshoku family. Ryuko is later revealed to be Satsuki’s presumed dead younger sister during the battle at the Honnouji Academy Cultural & Sports Grand Festival, revealed to have become a human infused with Life Fibers as the result of her being experimented on as a newborn baby by their mother Ragyo.
In the final battle, Mako encourages her by promising a date afterward.