My Other Half

My best friends are my solitude, my violin and my weapons.
My reason of living is to survive in a world of ruthlessness and terror.
My secret is my Other Half, my bloodthirsty second self.
My identity is a 16 years old girl passing for a boy.
My past is as dark as you could never think of.

All those things leaded me to the Mount Fuji, where I began a long and tremendous journey through another dimension with a bunch of ninja-knights and maybe even a bit of romance...