But there isn't any incest in the game >.< and even if there were, it's not my story. I've just localised a Japanese drama CD to English and turned it from an audio-only CD into a playable game.
I get what you mean though because the strange step-brother/sister trope appears in the first volume of the CD. I don't know why it seems to be a thing in Japanese media that characters have the hots for their step-siblings, and it's not a trope that I personally enjoy as I also find it quite weird and a bit creepy. Still, I wanted this fan project to be as faithful to the original Japanese content as possible, so I kept it the same. If there were actually incest in the content though, I wouldn't have localised it in the first place >.<