Ultra Sword

Ultra Sword is a manga series by Shizuru Hayashiya. It was serialized in Comic MegaCube.

Plot
Shijou Mizuki is a girl who since kid has been sexually harassed, then she turns out to be a sacrifice to stop the demon of lust kurigura whose seal is broken.

Four girls with katanas have to protect her from being raped by kurigura, who wants to turn the world into an eromanga-like utopia