So, if we want a relationship with the sister, should we choose between her and the rest of the LIs? Because as I understand it, she can't be part of the harem.
Personally, I'm not convinced that some LIs can be part of the harem and others can't. In fact, if a LI isn't part of the MC's harem (because I choose it), I don't like her to have any kind of romantic or sexual relationship with him. But I have to be the one to decide that I don't like her, because if I like said LI but she can't be part of the MC's harem (she has a solo route or as a couple with another LI) and then I have to choose between her and a harem with other LIs that I also like, my choice will be to leave the game.
Of the image tags I like are romance, harem, and incest. So I hope that the MC's, I suppose, sister can also be part of the MC's harem.
I don't like any of the other tags (Except fetish trainer, which I don't really know what to expect).
Out of curiosity, does domination refer to femdom or maledom? I don't like either of them, but I like femdom less, and I tolerate maledom as long as it's incredibly gentle.
The fetish trainer thing is something that has me confused. I'm not sure if she trains the MC, the LIs, both, or herself. Nor what fetishes she could train. Because training to be a Yandere or a lesbian sounds weird.