Gun Princess

Gun Princess (銃姫, Jū Hime) is an ongoing light novel series written Madoka Takadono and illustrated by Katsumi Enami. The first novel was published under Media Factory's MF Bunko J imprint. A manga adaptation written by Takadono and illustrated by Kei Ichimonji was serialized in Kodansha's Monthly Shōnen Sirius magazine, and was later released in four tankōbon volumes.

Plot
Long ago, humans angered the gods and lost their magical powers. However, the humans refused to give their powers and discovered a way to seal magic into bullets. Since then, the world has lived in a state of constant warfare. Cedric, Ambrosia and Elwing begin a journey to find the Gun Princess, a powerful weapon that could change the fate of the world.