Ryou Seibai!: Gakuen Bishoujo Seisai Hiroku

Hiromi Yokoyama must be some sad, horrible person to be responsible for all the sad and horrible NTR-esque hentai under the "Suzuki Mirano" name.

Yet here comes a hentai title that atleast tries to break from its loop; asking if you, the male lead of an NTR-esque hentai, would really stand by and let your (sexy) sister be raped?

Kyoichiro answers that question with a HELL NO!! and goes out to seek revenge. After getting injured from a misunderstanding, he gets help from Yamiko, the school nurse. And so the plot unfolds. (Don't joke. Despite all the rape and such, there IS a plot.)

As with all hentai, ... most of the girls herein this title get turned into cum dumpsters pretty quickly. For the last girl, there's a reason for it.