Don't get me wrong though I love the discussion Its just when every other comment is about the sister thing it feels like people think its gonna be a big part of the game when in reality if it even makes it into the game it would be like 0.01 percent of content. maybe its just me and its not a big deal
I feel like the sister is not the point here, the point is showing a sexual scene that does not contain the MC, the possible candidate being a sister just makes it worse, but any scene that does not contain the MC is meaningless at best, harem games are about romance between a single guy and multiple girls, harem fans are generally unintressed in seeing other guys have sex, I personally find it disgusting, admittedly mine is an extereme stance, that does not mean others will like it, as you can see, I feel like you should not concentrate too much on the sister thing as that is missing the point, the point is only the MC and the girls are important, anyone else is either superflous or straight up detrimental, at least sexually, I already went in depth on some of the other tags and this falls into those, so do not worry too much about the sister, incest is not mandatory in a harem game, just really common, I have never seen people complain about the lack of incest unless the dev makes the relatives attractive and seem interesten in the MC, as long as there are no scenes or mentions of other guys you should be fine, family can not appear at all, the problem starts when you make them appear and make them have sex with someone else, people would definitely prefer a sister to appear and not have sex with anyone than one that appears and gets fucked by a random guy, many would drop the game because of that, having said that good luck in your endeavours
P.S. sorry for yet another wall of text but I felt the need to write this, a lot of dev work is about gaining trust, trust is very easy to loose and almost impossible to regain, when you say you want to learn the hard way I am sorry to say that is something devs don't really come back from, not without a drastic shift in target audience, a single bad scene could taint your game even if removed later, people will always wonder if there is ever going to be another problematic scene added, the problem is not really the sister, it is about managing expectations, you have done a pretty good job about making sure people know that incest is not planned and if anything close happens it will be a very small part of the game, the problem is that a single world can ruin a game, it does not matter how small certain things just ruin everything, this is not meant to be discouraging, only informative, people are complex but patterns are there, they are pretty easy to recognize by looking enough