Mariko Toujou

She is a world champion wrestler who came back to Japan to challenge Misaki in a special title match. She happens to be Misaki's former mentor who also applied the same arduous training method that the latter did to Sakura.

Together with Kanae and Misaki they use to to be known as "The Golden Age Girls" during their days when they are still together competing in wrestling.

(Source: ZincView)