Inma Seiden: The Legend of the Beast of Lust

At Ootori Academy, two powerful families — the Kameyamas and the Ootoris — are locked in a bitter war for control, clashing over a prestigious school where old money and older grudges run deep. That political drama alone would be enough to carry a story, but then students start getting attacked by a figure in an iron mask, and things take a sharp turn into supernatural horror territory. Sena gets hit first. Then Mao. Then Hitomi steps in to help, and you get the sense this goes way beyond a simple rivalry between families. There's something darker feeding off the chaos at this school, and nobody's figured out what it is yet. The six-episode OVA format keeps the pacing tight — you're never sitting through filler when the mystery is already this dense in the opening episodes. If you enjoyed the dark supernatural atmosphere of Bible Black or the demon-invasion framing of La Blue Girl, this fits comfortably in that corner of the genre. Arms Studio leans into the horror elements more than you might expect, giving the whole thing a genuinely unsettling edge underneath the erotic content. The masked antagonist is handled with enough ambiguity early on that you actually want to know who's behind the mask. Just go in knowing this is firmly adult horror territory — the school setting is basically set dressing for something much grimmer.