mato seihei no slave."mato" is a demon-filled dimension, and it has opened up to threaten humankind. a type of "peach" tree growing there yields fruit that gives special powers to anyone who eats it, giving a fighting chance to humankind, but this works only for females. thus, women become protectors of humanity, rising their social status, while men are relegated to second-class citizens who scrap for basic occupation and recognition.
cue yuuki wakura, a laborious and domestically crafty high school senior, has an older sister who has been taken during a mato event five years ago. while lamenting his future life's hardships, an event opens before him. while captain kyouka of the anti-demon corps rescues him from demons, she confers his powers as her "slave" and turns him into a mighty beast that slays all the demons.