Injuu Nerawareta Hanayome - Season 1

Sanshiro, a servant, harbors forbidden love for his master's daughter, Momoyo. He obsessively watches her through a ceiling aperture, tormented by his desire. When her fiance returns from overseas, Sanshiro despairs, but then witnesses the engaged couple engaging in sadomasochistic acts with each other and other household members. These depraved rituals, he comes to believe, are intended to summon a demonic entity. Resolved to protect Momoyo, Sanshiro decides he must intervene to stop her fiance's plans.