To be fair, I didn't mean "reskin" in a literal sense. I meant to imitate RLE by the book in a different environment. Taking Naruto, as an example, since it's a source that seems to be pretty popular among the porn parodies. Imagine Naruto-Like Shippuden, or some shit. You're Zeruto and you have the power to cancel chakra based abilities, you go to the ninja school and meet with conveniently +18 females around the area.
Now, I'm making this bs on the fly as I write it, but the idea of taking a popular existing story, with already popular established characters and background and make a H game where the MC is conveniently attractive for the gals around, in an environment where you can just occupy yourself with day to day stuff, slowly (or quicly) crawl up their pants up dem poontangs and being able to customize their looks and modify their behavior through stats doesn't seem overly complicated. Especially because when in doubt, you could revisit this game and try to think like an inspired Oni who actually would like to improve the game.