Elena Miyazawa

A member of the idol group Sweet Diva, she is Sakura's rival who is a tomboy and strong-minded, though, she may appear to be supportive of Sakura's plans to be a pro wrestler in order to redeem not only her honor but the group's reputation as well, she is actually jealous of Sakura for getting the top notch as the group's lead singer. It is hinted that she won't hesitate to take every opportunity to outshine Sakura, originally, it was her who got into a spat with Rio Kazama (eventually, Sakura got deeply involve after coming into her aide) because of Rio's insults about the two divas' (Sakura and her) poor choice of getting into wrestling as a promotional gimmick.

It turns out she's really Blue Panther.
(Source: Zinc-view forum)