Kämpfer

Kämpfer is a Japanese anime series which aired on Tokyo Broadcasting System. The series premiered on October 1, 2009.

Senou Natsuru is your normal, everyday high school student. However he's been chosen to be a Kämpfer, who's objective consists on fighting other Kämpfer with either guns, swords or magic, however, there's catch; first you can't chose if you're a Kämpfer or not, and second, you must have the body of a girl to use your powers.