Musashi Miyamoto

One of the members of the "Dark Samurai" who just like Jubei also uses a dual katana as her fighting weapon, though she is a sworn enemy of the master samurai's,she is also a frequent customer of their Buou Academy Maid Cafe and always wanted Jubei to be the one to serve her even though she calls the latter a "Fake." It was later in ep. 5 that she found out that Jubei is also a master samurai.

(Source: ANN Forum)