Senou Natsuru, an average second year high school guy, has been chosen by the Moderators to be a Kämpfer. Kämpfers are given a bracelet to activate their powers and fight the enemy. Also, Kämpfers can only be girls, so upon activation, a guy would turn into a girl.

The first four volumes of Kämpfer were published digitally in English by Digital Manga Publishing from December 3, 2014, to August 23, 2016.