Mouryou no Nie

Hunting monsters while being one yourself — that's the core setup of Mouryou no Nie, a 2-episode OVA from 2012 that leans hard into dark supernatural horror. Hayato, Chihiro, and Suzuna aren't human, but they've chosen humanity's side anyway, spending their days sealing away malevolent creatures that threaten the peace. It's a delicate existence — trying to protect a world that would probably fear you if it knew what you were. Then word gets out that the ancient monsters sealed away after a catastrophic war centuries ago are about to break free, and the trio has to head straight toward the source before everything falls apart. The premise has a layered tension to it: these characters are already caught between two worlds, and now they're walking into the worst possible version of both. If you liked the monster-coexistence angle in Devilman: The Birth or the creeping dread of Mouryou no Hako, there's a familiar atmosphere here — eerie, tense, with a mythology that actually has weight behind it. The sealing mechanics feel grounded in the world's lore rather than just being a plot device. Adapted from a visual novel by Studio Eromatick, it carries that source material's attention to character dynamic alongside its horror elements. Fair warning: the genres listed include hentai, so go in knowing what kind of OVA this is. Within that context, the supernatural worldbuilding is more developed than you might expect from something this short.