So far, all we know is that she travels with Tsunade. She appears to be a leaf village member, but does not where any leaf village head protector, like Tsunade. She probably is as strong as Kakashi since she appeared as if she was going to beat Kabuto, whom Oro considers is as strong as Kakashi. From ep 90, she was mentioned as the neice of the person Tsunade was in love with.

In another thread, she was mentioned as a probable team-mate of Kakashi, so probably an apprentice of Jiraiya.

Any thoughts on who she really is, why she is traveling with Tsunade, and how powerful she really is?